NEW HAVEN-President Ford last night told a gathering of Yale Law School alumni that the United States faces "a basic and serious problem of disregard of the law," as about 500 people outside protested his appearance.

Ford, who graduated from the Yale Law School in 1941, received a mixed reaction from the additional 300 people who watched his arrival at the commemoration of the 150th anniversary of the school's founding.

In his 40 minute address, Ford said that violent crimes and "crime in high places" have prevented the country from providing the "domestic tranquility" promised in the preamble of the Constitution.

He said it was the federal government's responsibility to provide leadership and funds to tighten the criminal justice system, in order to insure that all those convicted of a crime are sent to prison.

The president carefully distinguished "domestic tranquility" from a call for law and order, telling the nearly 1000 alumni and guests, "I do not seek vindictive punishment of the criminal, but rather protection of the innocent victim."

In his speech, Ford alluded to the Watergate scandal, claiming that his administration had made it the highest priority "to restore decency to the Executive Branch."

Before Ford's speech, 400 demonstrators, led by representatives of the Spartacus Youth League, the Ukrainian Liberation Front and a coalition of Greek Cypriots, marched at the Beinecke Library, where the reception was held.

Spartacus League representatives led a picket line while protesters chanted, "NLF won't stop now; onward to Saigon right now," and "All Indochina must go Communist." About 50 Greek Cypriots marched up and down the street carrying signs reading. "Turks-NATO Out of Cyprus."

As they marched, another coalition of community groups and Yale law students sponsored a "soup line" in Cross Common, a block away from Beinecke, distributing free bread and soup in what a spokesman called "a symbolic act against the country's economic situation."

The spokesman estimated that approximately 200 people participated in the soup line.

The 40 Yale University and New Haven policemen observed the demonstrations, holding open a pathway for alumni and guests entering the building prior to the $13.50-a-plate dinner.

Guests' Reactions

The entering guests expressed reactions to the demonstrators, some saying they were in full support of the protesters, others criticizing their "behavior."

Kingman Brewster, president of Yale; Gov. Ella Grasso of Connection; and Associate Supreme Court Justices Potter Stewart and Byron White were among the alumni who attended the gathering.