Army recruiters invaded suburban America in unprecedented force this year and scored big, according to Army officials.

They signed up so many bright high-school graduates that next month the Army will stop recruiting for this fiscal year and start stockpiling volunteers for fiscal 1983, which starts in October.

Lt. Gen. Maxwell R. Thurman, Army personnel chief, told The Post Friday that the Army's offer of college money, including $15,200 after a two-year hitch, proved the biggest drawing card. The recession also has helped the recruiting business, he acknowledged.

Not since the United States government scrapped the draft in 1973 and ordered the armed services to fill their ranks with volunteers or go short has the Army done this well in recruiting, the three-star general said.

"There is no bad news," he said of this year's results.

Thurman also gave credit to the Army's decision to find out where bright young Americans lived and to go after them. This involved moving some of the Army recruiting stations from the edge of railroad stations and bus depots to tonier locations, including the suburbs. The Army relocated 347 recruiting stations and opened 375 new ones in 1981 and 1982.

Suite 213 in Olney, Md., in Montgomery County, typifies the Army's new approach to young people who want to "be all you can be"--to quote the Army's latest slogan. The suite is located between dentist offices and a dance studio on the second floor of an office building in the Olney shopping center.

From Suite 213, Army Staff Sgt. Roxianne Lervick goes hunting at surrounding high schools, playgrounds and drugstores. She talks up the college money that is available these days from the Army but not from the other armed services.

Enlist for just two years, she tells them, and come out of the Army with $15,200 for college. The Army contributes all but $2,400 of that. The volunteer contributes the $2,400 through monthly $100 deductions from his or her pay, which starts at $551 a month.

To qualify for the college money, the volunteer must have a high school degree and score above the national average on the entrance tests.

As young people worry more and more about where college money will come from, Lervick said, the Army looks better and better. "They feel they can do anything for two years," she said in explaining the appeal of the Army's education money. "The trend is still: 'I've got to go to college.' " Three of her hottest prospects just lost their summer jobs, she said.

"The suburbs are a better market for the Army," said Capt. Donald C. Spiece Jr., who oversees Army recruiting offices in Montgomery County and downtown Washington. "In the city, you get lots of walk-ins but many of them are not qualified mentally. In the suburbs, we don't have that much of a problem."

Army officials said they did not yet have a computer breakdown on what percentage of this year's volunteers came from the suburbs but said they felt sure it is a record for the post-Vietnam period.

Thurman asserted that moving recruitment stations from downtown does not deny some blacks the chance to learn about the Army and perhaps join up.

The Army has kept many of its downtown stations open, he said, and spreads information through bulletins to high schools and advertisments on radio, television and in national magazines. He added that blacks are enlisting in about the same numbers this year as last.

While listing college money and the recession as the top reasons recruiters did so well this year, Thurman credited as well the improved image of the military, higher pay for officers and enlisted people and the marketing approach the Army has taken to recruiting--such as studying Census Bureau data and other statistics to zero in on bright America.

To underscore the last point, Thurman threw a chart on his desk. It showed that the combat arms--infantry, armor and field artillery--are getting much brighter people, if tests are indicative.

Of the people who have signed up for combat jobs this year, 51.3 percent ranked above the national average on the tests. This compares with 17.6 percent for fiscal 1980 in the higher mental categories, I through IIIA.

The Navy, Air Force and Marine Corps likewise have been doing well in recruiting finding more than enough quality people to fill their ranks. But the Army's success is the most significant because, as the largest service, it needs the most volunteers.

Do this year's recruiting successes mean that the All Volunteer Force is indeed a substitute for the draft? The jury is still out on that key question.

Thurman sees problems ahead if military pay is not kept competitive. He is especially concerned about the Army's ability to retain its middle management, both officers and enlisted personnel.

Putting away the good-news charts on this year's recruiting, Thurman said: "We have to pay the mid-range noncommissioned officers and middle-range commanding officers to make them stay with us."