On Dec. 8, Soon Ye O, a 38-year-old mother of six children and recent Korean immigrant, was shot to death as she was waiting on customers in the small grocery stores she and her family had opened only a week earlier.

The holdup at the O's store was one of 20 or 30 robberies in 1977 of small businesses owned by Korean immigrants in Baltimore. The stores are generally in blighted slum neighborhoods of Baltimore, areas often littered with liquor bottles and trash. Holdups are not unusual here.

But that's not the point. Like other immigrants in other generations, the Koreans have come here for a better life. They take whatever job they can get, save their money, and try to start their own business.

The Os hoped for no less. "As a wage earner I could work only eight hours a day. With my own store I could work more and save more. Someday we hoped to have our own house,"said Pak In O, the husband.

The store is closed now. With his six children sitting around him in the Falls Church house they rent, the 53-year-old Pak In O looked and sounded like a man in a daze, trying to make some sense of what had happened. It was Christmastime when he was interviewed through an interpreter and the cheery decorations and toys scattered around the crowded living-room were a cruel contrast to the picture of Mrs. O, draped in black displayed prominently on a table in one corner.

"She didn't have a good time in her life," he said. "She worked very hard, and she passed away before she saw a good life. My dream of being independent lasted only one week. I have my doubts about this country now."

Police believe that Mrs. O's murder was in part a result of her poor English. The teen-aged gunman tried to rob her and apparently panicked when she couldn't undertand him.

In the past few years, Koreans have become one of the fastest-growing of the many immigrant groups in the Washington-Baltimore area, their number now estimated at between 30,000 and 40,000.

O and his family came to Baltimore about three years ago, after working for 20 years as a mechanic at a U.S. Army base in Korea. It was a good life, but he was concerned about his children's future because high school is not provided free in Korea. He was told there were good schools in the Washington area, so he came here.

An unusual number of Koreans - like O - have bought grocery stores in the Baltimore-Washington area. "You can buy a small store cheaper than a lot of other businesses," said Soung Y Choung, who owns Jessie's Food Market in East Baltimore. "It's not that good for Americans and they want to sell them.

"There's a low profit margin so they can't afford to hire help. But because we don't have much money, we just have to work harder and use members of the family to help out. It's not so hard to learn the grocery business and people have to eat before they do anything.

But as Choung and others have discovered, such ventures carry high risks. Like other Korean businessmen, Choung bought his store from an elderly Jewish merchant in what was once a white ethnic neighborhood.

The original owners of small stores like Jessie's have by now died or retired, and since they succeeded in fulfilling the immigrant dream of bettering their families' lot in life, their children are not generally interested in carrying on the family business.

At the same time, the neighborhoods have changed, becoming predominantly low-income black areas. (In Washington, most Korean-owned stores seem to be located in less deteriorated areas than in Baltimore, perhaps accounting for the fewer crimes directed against them.)

Thus, today, Korean immigrants find themselves repeating the process other immigrant went through to become part of American society, but now with stores nobody else wants in areas with different ethnics neighborhood and high crime rates.

Other Korean grocery owners in Baltimore may not have suffered as greatly as O and his family, but many have had their share of crime and other problems.

Soung Y Choung has owned Jessie's Food Market, "The Store Everybody Talks About," in East Baltimore for three years. In his first six months of operation, he was robbed six times, a figure he now recites almost matter-of-factly in his halting English. After the sixth robbery he installed a bullet-proof protective window costing about $2,000 around the main part of the store and a special door-buzzer system. Now customers can enter the store only if the Choungs buzz them in.

Even after installing the buzzer system, though, he said recently, his wife was assaulted twice by customer who got violent after they got inside the store. Petty thievery continues. Young people especially cause problems: Just last month, a group knocked out the glass of his outer door. "We just stayed inside and watched them," he said. "There was nothing we could do."

He has become of calling the police for incidents such as this, he said, because he has already had one bad experience with the criminal justice system.

Early last year he caught a child stealing a bag of potato chips, and his wife lightly hit the child in trying to keep her from running out the door. A large crowd of neighborhood people came to his store afterwards and protested his wife's action.

Fearful that the crowd was getting out of hand, he called the police, but the results were not what he expected: Rather than the child being punished, his wife was charged with assaulting her and had to go to court.

There, because she speaks English poorly, his wife had a hard time, he said. "And the judge believed the child that she wasn't stealing," Choung says wonderingly. "They put my wife on probation, and had to pay a fine."

That sort of thing had played a part in convincing Choung he should eventually get out of the grocery business.

Some of those who stay in the business take extraorinary steps to protect themselves. The Yu-Jin Market in Baltimore prepared for the worst by transforming a neighborhood grocery store into a fortress.

An iron gate covers the door. The windows are boarded up. A sheet of bullet proof glass separates the entryway from the main part of the store, requiring customers to give their orders to the store owners through the glass.

The items are then passed out through a small window, also made of bullet proof glass. It is possible for the transaction to take place without any real contact between the customer and the merchant.

Another Korean couple, Kun T. and Myung W. Chon, has owned a grocery store in northeast Baltimore for two and a half years and were robbed for the first time early last year. After that they got a guard dog. And now, since the O murder, they too have decided to get a bullet-proof protective window.

Their life here, they say, is much harder than it was in Korea. There Chon worked as an equipment engineer, and they owned a large house. Mrs. Chon did not have to work and had two housemaids.

Now Mrs. Chon works 16 hours a day in the store with her husband, and they and their children live above the store in a four-room apartment.

Despite, the difficulties and the fear of crime, they still think they made the right move in coming here, Chon said, because "here we can make the children a better life."

The store-owners' concern for their children's future is typical of Korean immigrants here, says Dr. Keun Ho Yu, a psychiatrist and member of the board of the Korean Society of Greater Baltimore. He theorizes that their attempts to move up quickly in American life and their willingness to take chances to make a good living cause them to be victimized more than they might otherwise be.

Perhaps because Koreans seem to move rapidly from one class ot another, first simply being wage-earners, them store-owners, "there may be some element of jealously, even perceived competition" on the part of blacks in the neighborhoods they move into, he explains. "And because Koreans are very foreign to the American way of life, they may also be seen as vulnerable individuals," he says.

In the meantime, though, Koreans are continuing their movement upward in American society. Jong Chang, president of the Korean Businessmen's Association in Baltimore, may represent this movement toward the American dream as well as anyone.

He came here in 1969 with only $100 in his pocket, he says. He and his wife worked hard, first with a variety of jobs, then with their own Oriental-food grocery store. They scrimped and saved, moved on to other ventures, and today own not only a grocery store, but a gas station and travel agency with branches in Washington and New York. They live in a $100,000 home, he says, and drive a Cadillac.

"Koreans who come here want to establish a good life for their children, the second generation," says Chang. "They're like any other immigrant group that comes here."