President Reagan attempted yesterday to rebuild a bridge to parts of the Hispanic-American community by honoring five Hispanic youths at the White House. One organizer called the steamy crush in the East Room "not a famous-people reception but a people-of-America reception."

Looking at one honoree, Junior Rosado of Boston, who was wearing his U.S. Navy uniform, Reagan said, "In his letter Junior said he looks forward to good news because 'when I have a rotten day, it cheers me up.' Junior, I know what you mean." His audience of 400, dressed in cocktail party attire and leaving aside any bad feelings about the devastating impact of the federal social service cuts, cheered.

Several guests were able, though, to recite how the administration's budget cuts had affected them. Eva Martinez, the mother of one of the honorees, an employe of the Tucson public schools, said at least four professional positions in her office had been eliminated by the federal cutbacks. "But at least we are still in existence," she said.

Many of these guests were drawn to the White House by their loyalty to the Hispanic community or their hope of finding new ways to support social services. Kelly Greason, 20, whose father is unemployed and who appealed to several Tucson groups for her transportation, said, "I thought this was important because I have a commitment to higher education for youth."

The president, accompanied by Nancy Reagan and Vice President Bush, cheerfully congratulated all the youths who had been selected by the nonpartisan National Coalition of Hispanic Mental Health and Human Services Organizations. When he introduced Rodolfo Rene Fuentes of Weslaco, Tex., as a scholar, debater and football player, Reagan asked, "What do you play? Right guard, I was a right guard myself."

The other recipients, who also were congratulated by former Washington mayor Walter Washington, former Republican National Committee cochair Mary Crisp and chicken magnate Frank Perdue, were Felicia Martinez of Tucson, Kennedy de la Pena of Albuquerque and Sheila Ortiz of Oklahoma City.

The gathering was the first of several parties around town last night to raise money for the coalition's Youth Institute. "Gracias," said the president when he had finished his presentation and had received a painting in return. "Gracias."

The cordiality occurred at a time of strained relationships with some segments of the Hispanic-American community. Many Hispanics had been insulted by recent remarks of administration appointees Clare Boothe Luce and J. Peter Grace linking their communities with poverty and overpopulation. Luce's name was removed from the final program for last night's events.

In Congress, Rep. Robert Garcia (D-N.Y.) strongly opposes some aspects of the administration-backed overhaul of the immigration laws, the Simpson-Mazzoli Bill, because, said a spokesman yesterday, "he believes it would discriminate against people of brown skin." And Arnold Torres, national executive director of the League of United Latin American Citizens, the largest Hispanic organization in the country, in commenting on the reception yesterday said, "This administration has had an unprecedented negative impact on our community. The reception will allow the president to say he has helped one Hispanic group."

The coalition of 250 agencies has had 33 percent of its federal money cut. "We have started working more closely with the local community. We firmly believe we need to help ourselves a little more," said the coalition's national executive director, Rodolfo Balli Sanchez. Sanchez is a lifelong Republican, he said, laughing, "except for the one time I voted for Rep. Ron Dellums (D-Calif.) when I was a student at Berkeley."

William Meinhofer, the executive director of La Sociedad Latina Inc., a coalition of social service agencies in Boston, works with one group that has had a $1 million cut, but he attended because one of his program's participants was an honoree. "The average cuts with our groups are 50 to 70 percent of their federal moneys," said Meinhofer. "But it's bad to feel sorry for yourself. If there is a penny out there, you will get it. The groups that are enduring are the strongest ones. That's not to say I am not still a Democrat and wouldn't vote against Reagan the next time."