In an opinion poll of American blacks, former presidential candidate Jesse L. Jackson emerged in unprompted responses as the only widely recognized spokesman for blacks.

The survey, taken by black interviewers, was sponsored by the Simon Wiesenthal Center, a Los Angeles-based organization for the study of the Nazi Holocaust. The center's leaders sought to gauge the black community's recognition and support of Nation of Islam leader Louis Farrakhan after his recent 14-city speaking tour.

Asked to think of "spokesmen for blacks who are well-known nationally," 59 percent named Jackson, who campaigned for the 1984 Democratic presidential nomination, 13 percent named Atlanta Mayor Andrew Young and 7 percent named Farrakhan. (Nine percent named the late civil rights leader Martin Luther King Jr.) Other leaders mentioned were Los Angeles Mayor Tom Bradley; Chicago Mayor Harold Washington; King's widow, Coretta Scott King; NAACP President Benjamin L. Hooks; former representative Shirley A. Chisholm (D-N.Y.); the late Black Muslim leader Malcolm X; Georgia state Sen. Julian Bond, and actor Bill Cosby.

The names of several leading blacks were then read to the respondents and interviewers noted which names were recognized. Jackson, whose favorable ratings were far above any other leader in the poll, was recognized by 100 percent of the respondents when the unprompted and prompted responses were totaled. On that scale, Farrakhan dropped to sixth place behind Jackson, Coretta King, Young, Bradley and Hooks, with a total of 51 percent recognizing him.

The poll showed that 54 percent of blacks who had heard of Farrakhan thought well of him and that 34 percent viewed him unfavorably, a negative rating seven times greater than that of any other prominent black public figure.

Thirty-eight percent of the 500 blacks in the national telephone sample agreed with the statement that "Jews have too much power in America." This was higher than the 23 percent of all non-Jewish ethnic groups that endorsed the same statement in a similar 1981 survey. Forty-one percent of blacks surveyed this year disagreed with the statement.

Randomly selected blacks were interviewed, and their responses were adjusted slightly because of underrepresented poor and low-education groups.

Peter Ellison and Sid Groeneman, coauthors of the survey report by Washington-based Market Facts Inc., said they were surprised to find that 51 percent of blacks feel that there is more racism in the United States today than 10 years ago. Forty-one percent disagreed with the statement.

Farrakhan was rated most favorably by those with the least formal education and the lowest incomes. People with college educations and higher incomes, younger blacks and males were somewhat more likely to say that Jews have too much power. Those respondents with an opinion on the issue also indicated that they think blacks are treated better by Jews than by non-Jews.

Asked if Americans could help end apartheid by selling their investments in South Africa, 34 percent agreed, 35 percent disagreed and 30 percent had no opinion. The poll has an error margin of 4.5 percentage points.