Rhonda Cleaves grew up in Paterson, N.J., and was one of only a few blacks in a nearly all-white high school. Now she's a 20-year-old junior at Voorhees College, a tiny all-black school outside this southern town.

She picked Voorhees, she said, because she wanted to try something different. But the move from the urban Northeast to the rural South was almost too much at first.

"It was so quiet. Oh God, I said, there's no traffic, no McDonald's, no taxis," she said. Her southern classmates were hard to adjust to. "They didn't question things like we northerners did."

Now Cleaves loves it at Voorhees, an 84-year-old school that started with 14 students in one room and now has 620 full-time students. "I can see the middle ground," she said. "I've been both places."

Not long ago, young blacks didn't have Rhonda Cleaves' choice about where to go to college. When the Supreme Court outlawed segregated schools in 1954, about 90 percent of the nation's 200,000 black college students attended historically black schools like Voorhees.

Today, out of a national total of 12 million college students, about one million are black, but the enrollment in black colleges has increased only slightly. Only about 200,000 of the black college students are enrolled in the 110 predominantly black schools. Still, with one-fifth of the total black enrollment, those schools produce about half of the black graduates.

Questions have been raised about the quality of education at black schools, their ability to offer competitive courses--especially in technical fields--and even their relevance in an age where qualified black students are sought out by other campuses.

But a recent look at the status of black colleges shows their leaders convinced about the need to carry on their long tradition in American education, even as they admit concern about growing financial and academic challenges. They insist black schools are especially needed to help academically deficient youngsters who might not get a chance elsewhere, and to build young blacks' confidence so they can enter a white world.

Any list of concerns starts with money. Most colleges have been strapped financially in recent years. But black schools are even more vulnerable, according to Elias Blake Jr., president of Clark College in Atlanta and head of the National Advisory Committee on Black Higher Education, because many have small endowments and most of their students are dependent on federal financial aid.

The black schools start behind in the fight for dollars because average black family income in the United States is only 60 percent of the white family's, Blake said. They also face increased competition from community and junior colleges for a piece of $150 million a year in special federal funding for "developing institutions."

Blake noted in a recent interview that black college enrollment has climbed in direct proportion to increases in such federal aid as Pell grants for students from needy families. Thus, the threatened Reagan budget cuts are especially troubling to black college leaders.

The Reagan administration has been sending mixed signals to black colleges. The president recently signed an executive order promising more financial help, but there were no dollar signs in the order. Meanwhile, the financial aid cuts are real and growing.

Pell grants for this fall were cut $80 to a maximum of $1,670 before Office of Management and Budget Director David A. Stockman started in on the college aid programs. In mid-September, a Senate appropriations subcommittee lopped nearly $300 million off the $2.65 billion earmarked for Pell grants for next year.

In Blake's view, it is shortsighted to cut programs that are reaching thousands of poor youngsters and giving them a chance for a college education. "These programs work," he said. "These young people are not going to be on the welfare rolls, they are not going to be out of work."

Black college officials already are taking steps to cope with the financial realities. At Tougaloo College in Mississippi--where the enrollment this fall is off more than 12 percent, from 815 to 715--President George A. Owens has restricted travel and long-distance calls and hopes to replace some of his custodial staff with part-time student help.

At Virginia Union University in Richmond, on the other hand, enrollment jumped 10 percent this fall to nearly 1,300. A $1 million federal grant expired, but President David T. Shannon said he covered the loss by cutting 12 of his 70 faculty members as well as dispensing with some low-enrollment classes.

Rather than looking to the federal government for financial help, Shannon said, he is turning to his alumni, to churches and to the Richmond business community. "We've picked up one of the planks of the president's executive order and are asking the private sector to give more," he said.

Shannon has no problem justifying the existence of his school. He rattles off a list of Virginia Union graduates ranging from the Richmond mayor and a federal judge to half the black doctors and schoolteachers in town. "The bottom line for us is the production of leaders, and not just blackness," he said.

Samuel L. Myers, executive director of the National Association for Equal Opportunity in Higher Education, an umbrella groups for black colleges, likes to point to a recent $20 million gift to member schools from the Mott Foundation as a sign of confidence in the future.

Niles White, lobbyist for the United Negro College Fund, noted that a capital campaign raised $60 million in three years. But he admits that some of his group's 41 private black schools could go under in the next few years without new resources and more diverse academic programs to attract students.

At Voorhees, President George B. Thomas, a former associate superintendent in the Montgomery County, Md., schools, is trying to beef up academic offerings, but declining enrollment is making it difficult. Five years ago, Voorhees had more than 1,000 full-time students, compared to this fall's 620.

About 98 percent of Voorhees' students receive financial aid. "Any further reductions does indeed threaten our existence," Thomas said. Shirley Hugee, financial aid director, said that last year 60 percent of Voorhees' students didn't have to contribute any cash for their schooling because a mixture of state and federal aid covered everything.

She and some other black administrators aren't sure that is such a good idea. Hector Sheppard, the school budget officer, said, for instance, "I was opposed to that because it's not real life. We're supposed to be preparing young people to face reality, and if everything comes too easily they may go out expecting the same in real life."

But a good many of the black colleges' students already know about reality and things not coming too easily. Voorhees student Charles Gore, for instance, is 19 and has four sisters and five brothers. His mother is a janitor at a school near their home in Nichols, S.C., population 617. His father, he says candidly, has a drinking problem.

Most of the other young black men in Gore's high school class went into the military or started looking for work after graduation, but a sister challenged him to go to college instead. So he did, with the help of a financial package that covers all but about $25 a month of Voorhees' $4,200 in fees. He is the first man in his family to go to college.

The Reagan budget cuts haven't reached Gore yet, although he said he'd be hard-pressed to find the money to stay in school if his aid package is reduced much. He picked tobacco this summer and is on a work-study program at school. He's taking some remedial courses now, is looking ahead to studying computer science and hopes for a shot at becoming an Air Force pilot.

"I'm going to strive," he said. "I'm going to college to try to help my mother. To repay her for some of the things she's done for me."

Myers, of the National Association for Equal Opportunity in Higher Education, said he didn't feel young blacks were being sheltered in an all-black college environment. "They have to be rooted in their culture," he said. "They have to build their confidence and sense of security, and then they'll be better able to negotiate in a white world.

"I don't want to call it an incubator, but, given the racism in the wider society, perhaps a little shelter doesn't hurt, but prepares one for integration."