Eight of ten Americans consider AIDS a threat to the general public, and the disease equals cancer in being named as the greatest perceived health problem facing the nation, according to a Washington Post-ABC News Poll.

But despite evidence of such strong concern, the national survey suggests that there is not a public panic about the disease. It suggests that this may be so in part because a significant percentage of the population is knowledgeable about who gets the disease and how it is spread.

Three of four people said they were not afraid of picking up the virus that causes the disease. A similar proportion said they were not taking special precautions to avoid exposure to it.

And despite widespread public debate about whether children with AIDS should be allowed to attend public school, more than six in 10 adults favored allowing it if health officials say there is no danger.

Fewer than one in five said that they would be very upset at a proposal to locate an AIDS patient-treatment and housing center in their neighborhood.

Although a majority did not favor more restrictive actions against AIDS victims, a significant minority did. Nearly one-third opposed having children with AIDS attend school. And just over one-fourth said they favored putting people with AIDS "into quarantine in special places to keep them away from the general public."

About 20 percent shared both these views. In addition, about one-third of those polled believed it was unsafe to associate with someone who had AIDS, even if there was no intimate physical contact.

Federal health authorities have repeatedly stressed, and the media has repeatedly reported, that the disease appears to be spread only through intimate exposure to bodily fluids, mostly through sexual contact, and not through casual contact. Many of those sampled accurately reflected some of the main points made by officials and the media.

In the poll, 48 percent thought they knew "a great deal" or a "good amount" about AIDS; 63 percent had a good idea of the number of reported AIDS cases to date; about 75 percent knew that it affected particular groups of the population, mostly homosexual men, as well as drug addicts and hemophiliacs.

The opinion poll is one of the most extensive conducted to date about public knowledge and concerns about AIDS, or acquired immune deficiency syndrome.

The results are based on a representative national sample of 1,512 adults 18 years and older in the continental United States surveyed by telephone Sept. 19-23. There is a theoretical margin of error of plus or minus 3 percentage points.

Since the disease was detected in 1981, it has afflicted more than 13,000 Americans, killing half of them thus far and threatening the lives of the others.

It has an incubation period of several years, mounting a slow attack on the body's immune system that, in the severe form of the disease, is almost invariably fatal. There is, as yet, no cure.

Follow-up interviews with some poll participants indicated that views on AIDS are affected by fears of the unknown and of the lethal nature of the disease, as well as by ambivalence about what to do about it:

"AIDS is the most important health problem. It's so widespread in such a short time. It's an epidemic," said a divorced mother and social worker from northern California.

"But I don't stay up nights losing sleep about it," she added.

"If you have it, you die. There is no cure . . . . It's more serious than cancer because it's more unknown," said a grandmother from Stamford, Conn. She initially said she favored some sort of quarantine of AIDS patients, but modified it to say they should "voluntarily stay clear" of others. "If I knew someone that had it, I'd talk to them. I certainly wouldn't like to be kissing them."

"I wouldn't worry about myself. I worry more about my kids," said a New York City seventh-grade math teacher and mother of four who wavers about whether children with AIDS should be in school. But, she adds, "I guess the parents out in Queens N.Y. were too panicked. I don't think that boycott was really called for."

"AIDS is the most important problem. It seems like it is the thing that is getting the most attention. Nobody knows what or how to deal with it or nothing," an unmarried Rochester, N.Y., grocery clerk said.

"A lot of people are scared of it," said a 23-year-old tire repairman from Green Bay, Wis.

"The longer they don't come up with a cure, the more people are going to be scared," said another single, young man who manages a Long Beach, Calif., liquor store.

"For a lay person, I'm as informed as anyone else. I'm still scared," said a local journalist who has written on AIDS. "Everyone should be terrified. But we should not allow it to turn ourselves into a closed society where ignorance prevails over reason. A massive influx of dollars and research should be poured into it simply because heterosexuals such as myself are also at risk."

About half of those polled thought the government would be spending more money on AIDS research if the disease did not mainly afflict homosexual males, and 71 percent said they would be "willing to pay extra taxes if that money were used to find a cure for AIDS." By 41 percent to 26 percent, people approved of the way President Reagan is handling the AIDS situa- tion.

The poll showed widespread public awareness about the disease. Nearly everyone said it is spread through intimate sexual contact, blood transfusions and the sharing of intravenous needles. (Two in three remained fearful of getting AIDS from blood transfusions despite recent national implementation of a test that screens contaminated blood.)

Despite authorities' reassurances, however, there were divergent views about whether the disease is spread through casual contact.

Fifty-six percent thought AIDS is less contagious than the common cold. But 19 percent said it was about as contagious as the cold, and 17 percent said it was more so.

Twenty-two percent thought AIDS could be passed by "being sneezed on," 16 percent from "sitting on a toilet seat" and 7 percent from "shaking hands."

Although 77 percent said they were taking no precautions against AIDS, 22 percent cited a wide range of actions they hoped would prevent their exposure to the disease.

At the top of the list of precautions was avoiding or being more careful in public restrooms or facilities, followed by avoiding contact with homosexuals or socializing less and avoiding strangers. Many of those polled said they were cutting down on sexual activity, having sexual relations with only one part- ner or limiting the number of part- ners.

Twelve of 21 men who identified themselves as homosexual or bisexual said they are doing something to limit their exposure to AIDS, particularly changing their sexual behavior.

In terms of public action, while 62 percent favored admitting children with AIDS to school, 78 percent also thought that "school officials should tell parents if a child with AIDS is attending their child's school." There was even division about whether "public school employes found to have AIDS should be taken off the job."

Overall, those with more knowledge tended to be less fearful of associating with AIDS victims and less likely to support restrictions, such as possible quarantine of those with the disease.