A Miami jury yesterday found Bolivian Roberto Suarez Jr. innocent of charges that he conspired to import cocaine into the United States two years ago as part of the Drug Enforcement Administration's biggest international "sting" operation.

His acquittal, a DEA official said, will have serious implications for American plans to encourage the new Bolivian government to crack down on the growing of cocaine in that country.

"This is going to wreck us in Bolivia," he said. Referring to future U.S. requests for extradition of accused cocaine traffickers from Bolivia for trial here, he added, "Now they won't send us anybody."

Federal prosecutors had charged that Suarez was at a jungle airstrip in Bolivia when an old Convair airplane, manned by five undercover DEA agents posing as American gangsters, picked up 854 pounds of cocaine worth $9 million.

Suarez told the jury in federal court in Miami during often emotional testimony this week that he was there at his father's request and did not know what was going on.

Four DEA agents testified that the younger Suarez participated in loading plastic bags filled with coca base into the plane.

His acquittal after two days of deliberation by the jury was greeted with surprise and tears by the 24-year-old, American-educated Suarez. Because he had been extradited to this country from Switzerland without a visa, the judge released him into the custody of his lawyer and told him to take the next available airplane to Bolivia.

The prime object of the 1980 "sting" operation, according to DEA agents, was his father, Roberto Suarez Sr.

The elder Suarez, they have alleged, controls a vast coca-leaf growing area in Bolivia and is one of that country's major cocaine dealers. He had been indicted in 1980, along with his son and two others, for conspiring to import cocaine into the United States. He has maintained that he is innocent.

Bolivia, according to recent federal reports on narcotics traffic, is the source of almost half the cocaine coming into the United States.

For several years, U.S. officials have been trying to convince the Bolivian government to reduce the amount of cocaine grown there and, since 1981, to turn the elder Suarez over for trial in this country. The younger Suarez was picked up in Switzerland in August.

Earlier this year, the two other Bolivians indicted in 1980 pleaded guilty to participation in the "sting" operation. One of them testified for the prosecution in the Suarez trial.

The United States is negotiating with the La Paz government for a new multimillion-dollar aid program that includes $30 million to increase enforcement of narcotics law in Bolivia and cut down on coca-leaf growing