While prejudice against Jews still persists among a minority of Americans, it has declined significantly in the United States in recent years, according to a new nationwide survey conducted for the American Jewish Committee.

Measured against a similar study published in 1964, the latest survey by the public opinion research firm of Yankelovich, Skelly and White shows a "definite decline in anti-Semitic stereotypes of Jews," according to Ruth Clark, who oversaw the face-to-face interviewing of more than 1,200 persons participating.

While the percentage of persons holding "highly anti-Semitic" views declined from 19 to 9 percent and those who, for example, regarded Jews as "shrewd and tricky" dropped from 40 to 27 percent, Clark said there remain serious pockets of prejudice. Almost half the blacks interviewed, she said, held anti-Semitic views.

"It's not a rosy study, but the country is in better shape in 1981 than in 1964," she said in describing the preliminary findings to a session of the American Jewish Committee, which is holding its 75th anniversary meeting here this week.

Her report came amid anxiety expressed by Jews at this week's meeting that a recent rash of anti-Semitic incidents could indicate a higher prevalence of prejudice than the study found.

The reported incidents -- painting swastikas on synagogues, desecrating cemeteries and the like -- numbered 377 in 1980 compared to only 129 "anti-Semitic episodes" in the United States during 1979. Officials of the American Jewish Committee, which was founded to combat prejudice, largely discounted such actions as those perpetrated by teen-agers unaffiliated with any organized hate group.

The survey did not include teen-agers under 18, a group Clark described as "a little frightening . . . aimless and thrill-seeking."

She attributed the overall decline in anti-Semitic feelings among other age groups to "generations changing rather than people changing." She said, for example, that today's 18- to 35-year olds are less prejudiced than those in that age bracket in 1964.

The decline in prejudice was often not perceived by Jews, the survey found. Fully three-fourths of the 174 Jews included in the survey, for example, thought that Gentiles felt Jews had too much power in the business world, while only a third of those interviewed actually expressed such a view. Similarly, only 16 percent of non-Jews "pushed in where they weren't wanted," but half the Jewish persons interviewed thought non-Jewish Americans held that view.

Milton Himmelfarb, the AJC's director of information and research, said the survey results confirmed the group's own informal findings that "in general, there's a hell of a lot more tolerance and absence of hatred toward 'them others.' Nowadays, we're lost in the mob."

The overriding note struck by the committee officials was one of caution, a warning not to overreact to specific incidents and thereby inflate their importance or inspire imitators. One paper distributed to conferees advised Jewish community leaders to implement a "quarantine principle" when such incidents do occur. "Where possible, avoid undue publicity," the paper advises.

"Wherever possible," the pamphlet adds, "take measures to insure that the Jewish community response is not dictated by extremist groups."

That incidents are not always what they appear was illustrated by one Los Angeles occurrence. The youths who shot pellets through windows of the Simon Wiesenthal Center for Holocaust Studies there, a California AJC leader said, turned out to be two Jewish teen-agers engaging in random vandalism.

"The bottom line in Los Angeles," said Bruce Ramer, the Los Angeles chapter president, "is anti-Semitic activities seem to have receded drastically" in recent months.

Nonetheless, an undercurrent of concern and unease persists. "Even if we think it's just an isolated bunch of crazies, remember, in the beginning, didn't the German Jews think Hitler was a crackpot?" asked Rose Miller, of New Jersey, which had 69 reported anti-Semitic incidents last year.

"My own sense is anti-Semitism is out there all right," said Samuel Rabinove, an attorney with the AJC. "You don't want to feed the paranoia, but don't belittle it where it is manifest. . . ."

"There are a lot of Gentiles who don't hate us but are not overly fond of us," Rabinove said. "It is not anti-Semitism. If push comes to shove, maybe we can't rely on them to be overly supportive."