Virginia Gov. Charles S. Robb, a man too conservative to win organized labor's endorsement last year, stood before an applauding state's AFL--CIO convention this morning smiling broadly as the labor delegates gave him a standing ovation.

It was a clear sign that organized labor has made its peace with the Democratic governor and is on the verge of endorsing Lt. Gov. Richard J. Davis, Robb's former running mate, for the U.S. Senate.

Robb, not known for his wit, could not let the moment pass and recalled that he had been barred from addressing the convention last year. "I liked your welcome this year better than last year," he quipped as his audience roared with laughter.

The AFL-CIO's warm reception seemed to mark a personal triumph for Robb, whose support for the state's right-to-work law and opposition to collective bargaining for public employes made him the first statewide Democratic candidate in a decade to be denied organized labor's endorsement. But Robb was the first Democrat to win the governor's office since 1965 and the labor delegates made it clear today that they want to be known as a friend of a winner.

"He's the governor. He's the man with whom we must deal," said Robert A. Stewart, executive director of Council 30 of the American Federation of State, County and Municipal Employees, which has 3,000 state members. "We are anxious to establish a positive relationship with him."

Absent from Robb's speech was any direct plug for the 60-year-old Davis, a mortgage banker and former Portsmouth mayor who shares the governor's views on the state's labor laws. "I'm just as nonpartisan as they come -- you know that," he joked with reporters after his speech to the 600 labor representatives in the ballroom of the Hotel Roanoke. "I was not invited to make a political speech as such."

If Robb's politics were obscure, John Perkins, director of the AFL-CIO's Committee on Political Education, the labor group's political action arm, was blunt. "You have a tremendous job to do," Perkins told the convention today. "Send us fresh troops from Virginia to the U.S. Congress. Send us Dick Davis for the Senate and at least five new congressmen for Virginia."

Despite Davis' opposition to repeal of the right-to-work law, which prohibits mandatory membership in labor unions, delegates here said his record in forging coalitions between labor and management in Portsmouth would virtually guarantee him the convention's support. "Even if he won't necessarily work for us, he won't work against us either," said one delegate.

The governor today took a subtle swipe at Davis' Republican opponent, Newport News Rep. Paul S. Trible Jr., criticizing "those who would try to divide us--those who would use the old tactic of labor baiting."

In recent weeks, the Trible campaign has distributed a memo that accuses Davis aides of soliciting labor contributions at a COPE meeting in New York. The Davis campaign has denied attending the meeting or seeking the contributions, and Davis supporters have attacked the memo as an antiunion smear.

The impact of an AFL-CIO endorsement on Davis' chances is unclear. Virginia has an antiunion tradition that stretches back to before the Civil War, and conventional political wisdom here has held that any candidate branded as an ally of labor is almost certain to lose.

A labor endorsement, however, would almost surely bring money that is much needed by Davis, who was drafted as his party's candidate two months ago. This week, Davis strategists acknowledged that they had raised only $450,000 to Trible's $1.2 million, and $100,000 of that had been contributed by Davis himself. In 1977, labor groups gave $220,000 to Democrat Henry E. Howell's unsuccessful campaign for governor.