The nation's oldest Hispanic civil rights organization opened its 54th annual convention today with a scathing attack on the Reagan administration and with dreams of attaining some of the recognition and success of its black counterparts.

About 200 delegates from the 100,000-member League of United Latin American Citizens (LULAC) gathered at the Renaissance Center downtown heard league President Tony Bonilla open the four-day gathering by telling the audience that "A lot of the blame for our present condition . . . we place at the door of the White House."

Since President Reagan took office, Bonilla said, the nation's estimated 15 million Hispanics have lost their only member on the U.S. Civil Rights Commission--Blandina Ramirez-Cardenas--and been hard hit by the administration's economic policies and budget cuts.

"If we had to describe this administration in civil rights, we could describe it as a cockroach administration," Bonilla said, "because everything they've touched, they've messed up."

Bonilla also criticized the administration's foreign policy in Latin America, saying that the league shared Reagan's opposition to communism and repression, but not what he called its belief that "you have to solve political, economic and social problems with violence."

Detroit is an unlikely site for this convention. The Motor City's Hispanic population is small, even though Gov. James Blanchard (D) welcomed the convention by saying he would not have been elected without Hispanic votes.

But moving the LULAC convention out of the Southwest, where Hispanic population is largest, is part of Bonilla's effort to expand the national media's concept of the civil rights movement--even at the expense of lowered attendance because many delegates cannot afford to travel this far.

Too often, many middle-class Hispanics here said, civil rights have been identified almost exclusively with blacks, who for so long have been the principal minorities in nation's political, economic and media strongholds.

Bonilla said Hispanics felt neither threatened by nor jealous of blacks, but certainly envious.

"Hispanics, up until now, have not learned to exercise that political and economic power, and it's been to our detriment," he said.

Former Justice Department attorney Ivonne Gonzalez Morales recalled investigating complaints of housing discrimination throughout the United States in the early 1970s and finding many black complainants and few Hispanic ones.

"Hispanics were the most forgotten segment of American citizenry because they have the language barrier," she said. "On the other hand, the NAACP . . . has been very successful . . . because they have learned how to play the game."

Representatives of black civil rights organizations will address the convention later. Among them will be the Rev. Jesse Jackson of Operation PUSH, chief advocate of a black presidential candidacy in 1984. Jackson is appealing for a coalition of blacks, Hispanics, women and others to rally behind an issue-based black candidacy.

Most of the announced Democratic presidential candidates will be here, starting tonight with Sen. Gary Hart (Colo.) and later Sens. Alan Cranston (Calif.), Ernest F. Hollings (S.C.) and John Glenn (Ohio)--who has the prime spot on the program--as well as former vice president Walter F. Mondale.

Hart spoke to 200 persons at a Hispanic fiesta that was driven inside the hotel by the same rainy weather that forced a one-day postponement in the traditional Freedom Festival fireworks on the Detroit River.

Hart promised "total and complete" enforcement of civil rights laws, a Latin American foreign policy based on human rights, efforts to end the nuclear arms race and more programs aimed at Hispanics and other minorities.

"Our goal for the 1980s for minorities and women must not be just jobs," he said, "but the right and opportunity to create jobs through ownership and management of their own businesses."

Bonilla said the league would like to hear candidates discuss their views on increased jobs training and public service jobs, more aid for educational programs, including loans for colleges students and funds for bilingual education, more economic and less military aid for Latin American countries and more Hispanic representation in top administrative posts.

He said the Reagan administration had appointed fewer than 40 Hispanics, many of whom have since left government and one of whom was the president's chauffeur.

"I would think," Bonilla said, "that after 400 years Hispanics ought to be entitled to something more than the chauffeur of the president of the United States."