Vice President George Bush yesterday used the convocation speech to graduates of Howard University to try to assuage black fears about President Reagan's commitment to equal opportunity and the impact of the administration's budget cuts on minorities and the poor.

"I know that many members of America's black community, along with other minority communities, have serious concerns about the philosophy of the Reagan administration on the paramount issues of civil rights and equal opportunity," Bush told the crowd, gathered at Howard Stadium for the school's 113th convocation.

"Let there be no doubt among minority Americans regarding the commitment of this administration to our nation's civil rights laws," he said.

Bush's speech to 1,000 graduates of one of the nation's most prestigious black universities and their guests contained many refrains from earlier addresses to predominantly black audiences. He quoted poet Langston Hughes, pledged more money to black colleges, promised to put black America back to work and condemned the recent surge in racially motivated violence.

"Let the white hood and the swastika, those ugly symbols of hatred and bigotry, be buried in the past, for there is no room for racial or religious intolerance in America," Bush said.

Among many of the nearly two dozen graduates interviewed afterwards, jubilant at passing one phase in their lives but uncertain about the next, Bush's words were taken skeptically.

Anthony Bourbon Reams of Los Angeles, who was graduated with a DDS degree from the College of Dentistry, said, "It always tickles me to no end how black folks get these type folks to come down here and talk.

"I thought they could have gotten [N.A.A.C.P. Executive Director] Benjamin Hooks or somebody. But the school depends largely on the federal government for support, so it's all politics. We just had to smile and be nice."

The vice president was forced to speak over the chants of a few dozen sign-waving demonstrators, who stood behind a chain-link fence about 50 feet from the stage. Directly in front of Bush, about 40 members of the graduating classes stood up and turned their backs to the vice president at the opening of his remarks. A few of the graduates waved red flags and red hankerchiefs.

The protests had been called for by a handful of students opposed to Reagan administration's social programs and foreign policy, as well as Bush's former role as director of the Central Intelligence Agency. Some of the students had preferred that the honorary degree given to Bush be bestowed instead on Robert Mugabe, prime minister of Zimbabwe.

Bush made one slight reference to those graduates standing with their backs to him, at the end of his prepared speech when he said, "The graduating class of '81 and the members of this audience here at Howard are headed in the same direction." Then he added, laughing, "although if you look around out there you wouldn't know it."

While the visible protest had little support, some graduates talked afterwards of their private reservations and feelings of uncertainty about the future for black Americans preparing to enter the economic mainstream under the Reagan administration.

"I'm glad I made it through before he started cutting B.E.O.G. (Basic Educational Opportunity Grants) and student loans," said Eric Lamar, a graduating senior from the business school. "I never would have made it through without those things.

"But then I look at my nephew," Lamar said, pointing to a lanky high school-aged youngster standing next to him, posing for pictures. "He's going to need some of those same programs I needed. So now I feel an obligation to get out there and fight for them."

Bush was awarded an honorary Doctor of Laws degree. University President James E. Cheek thanked Bush for his "friendship . . . and continued advocacy of our cause."

Honorary law degrees were also granted to Dr. James Madison Nabrit Jr., who served as president of the university through most of the turbulent 1960s, and to U.S. Appeals Court Chief Judge Spottswood W. Robinson III, who was graduated from the university's law school in 1939 with the highest scholastic average in the history of the school.

An honorary Doctor of Humane Letters degree was awarded to Lt. Gen. Olusegun Obasanjo, who once headed the former military government in Nigeria.