More than 200 students at the University of Michigan yesterday ended a 24-hour blockade of an administration building. The protest was intended to focus attention on the prejudice that Blacks and other minority students face on the Ann Arbor campus.

Demanding that the university take actions they advocated to alleviate racism, the students blocked the entrance of Fleming Hall, the building that houses the university's top administrators, students and university officials said.

University workers yesterday foiled the plan by entering the building through a system of underground tunnels, but afterwards students confronted the university regents en route to a regularly scheduled meeting and coerced them into holding an impromptu open forum.

The students, three-quarters of whom were Black, presented the administrators with demands that they believe will help solve the problem of racism on campus. The regents did not agree to the demands at the open meeting yesterday, but they will hold another discussion with the students on Monday, said Joseph Osley, head of the university news and information office.

The two Black student groups involved in the protest--the Black Action Movement (BAM) and the United Coalition Against Racism (UCAR)--are demanding that the university follow through on its unkept 1970 promise to increase Black enrollment to 10 percent. Blacks currently compose about 6 percent of the student body.

Besides calling for the 10 percent quota, BAM's demands include the immediate granting of tenure to all presently hired Black faculty and the appointment of Black as chairmen of 30 percent of the academic departments.

In addition, BAM is asking for institutionalized means of punishing incidents motivated by racism, more Blacks running Black issue programs on campus radio stations, and the capitalization of "Black" in campus publications.

For its part, the UCAR is calling for a mandatory workshop on racism and bigotry, a required course for all students on racial prejudice, and tuition waivers for all underrepresented and financially needy minority students until quota goals are reached.

In an effort to increase minority representation in the student body, University President Harold Shapiro in February announced a plan to commit $1 million a year to a fund working toward improving minority recruitment and retention, according to university news office spokesman Joseph Osley.

In another anti-racist action, the university has also agreed to waive a bylaw that would prevent the institution from bestowing an honorary degree upon Nelson Mandela because he would not be able to accept in person, Osley said.

The sit-in is but the latest reaction against the perceived increasing expression of racist attitudes at the Ann Arbor campus, which students said is known for its prevalent racist attitudes.

While students said that racism, whether overt or covert, has always been a problem, this year has seen several incidents that have dramatized the problem and have motivated students and administrators to take action.

The incidents that have brought racism into the public eye, students said, were the anti-Black flier that was slipped under a door into a room where Black women were gathered last January, and a February campus radio station broadcast of jokes with racial slurs.

The flier "called for open [hunting] season on Blacks," said Wendy S. Lewis, member of UCAR. A 19-year old freshman has confessed to writing the pamphlet and been permanently barred from university housing, officials said.

The radio station, WJJX, was temporarily closed and the DJ was fired for the racial slurs he broadcast. A three-member panel appointed by university president Harold Shapiro is investigating the incident to determine what, if any, action should be taken against the students involved.

"Racism has always been a problem" at the university, said Lewis, a senior, but it has become "more overt and directed to violence" in last few years.

Racism is also an underlying cause in the high attrition rate of Black students, said Eunice Royster, director of the university's comprehensive studies program, which helps minority students with their studies.

Only 58.6 percent of the Black students entering the university in 1979 had graduated by 1985, a figure considerably lower than the 74.5 percent graduation rate for students as a whole, according to the campus newpspaper, The Michigan Daily.

Royster said that racism is not confined to the university, but that "attention has been focused on Michigan because of its excellent reputation as an academic institution."

"We are a premier research institution" that prides itself on being on the cutting edge of everything, Royster said. "You expect more from an institution of this caliber."

Royster said that graffiti such as swastikas painted on the buildings, and students cursing at minorities and even hurling objects at them indicates that racism is a part of everyday life at the University of Michigan.