Virginia labor and Democratic Party leaders worked energetically at the state AFL-CIO convention here today to head off the possibility of a vote Saturday to withhold an endorsement of Democratic attorney general candidate Edward E. Lane.

Lane's Republican opponent, State Sen. J. Marshall Coleman (R-Staunton) is actively lobbying labor representatives here, criticizing Lane for what he says is his "antilabor" and "anti-humab rights" record as a state delegate. Coleman is the only GOP candidate to attend the convention so far.

Meanwhile, Lane and his supporters have been emphasizing the importance of Democratic Party unity to the convention delegates of Virginia's most influential labor organization.

"I take it nobody has any problems supporting Henry Howell the Democratic gubernatorial nominee, the chairman of a private black caucus said today. "And no problems about Chuck Robb (the Democratic lieutenant gubernatorial candidate). Now are there any questions about Ed Land?"

That indeed was the sticking point - not just for a few of the blacks who had gathered to discuss the issue, but for some of the other delegates gathered here as well. On Saturday the convention will endorse - or choose not to endorse - candidates in the Nov. 8 election and the fact that the black caucus was meeting at all to discuss Lane was evidence of the reluctance some feel toward his candidacy.

Although observers do not expect Coleman to get the labor endorsement, some Democrats are worried the convention may vote not to endorse either candidate for attorney general.

Staffers representing Coleman were industriously passing out literature for their candidate in the lobby of the Hotel Roanoke, rivaled only by Lane supporters distributing their material, further evidence of the conflict.

Meanwhile, Howell supporters and Democratic Party stalwarts were working diligently to promote the concept of party unity answer Lane critics. Another frequently heard argument in support of the "rainbow" Democratic ticket is that the Virginia attorney general doesn't have much power and it's more important to elect a Democratic governor than be diverted by arguments over the attorney general's race.

The Lane flyer, entitled "A Sound Record for Working Men and Women," listed five pieces of legislation Lane has supported as a Richmond delegate in the General Assembly that benefit working people, including a $2.50 minimum wage in 1976. The flyer states that Coleman voted against this measure.

Meanwhile, the Coleman forces ("hatchet men," sneered one Lane supporter) are distributing a five-page handout. Inside are listed 11 bills that labor supported but Lane voted against, including a duty-free lunch period for teachers and a 1960 minimum wage bill. It also includes a list of "human rights and dignity" issues that Lane voted against, from the Equal Rights Amendment to a reprise of an earlier Coleman pamphlet detailing Lane's record on massive resistance a series of measures designed to prevent school desegregation in Virginia in th 1950s.

It is these issues that seem to be at the core of objections about Lane among moderates and liberals here and elsewhere in the state. They and the party response to them were discussed openly in the black caucus, which was attended by a reporter who was belatedly discovered and subsequently ejected.

"We're not asking anybody to love Ed Lane," chairman Earl Davis of the State AFL-CIO office said to the causcus. "You have to ask yourself, where is the power? With the governor. What can the attorney general initiate? Nothing! He had to do what the General Assembly tells him. I wouldn't care if it was ditty-y-ditty for attorney general as long as we can get the top spot."

Davis and others went on to exort the 20 or so who attended the meeting - few of whom openly had doubts about Lane - to be conscious of political realities rather than "an emotional issue" such as massive resistance.

"We can't talk about the past, we've got to damn sight talk about the future" said a man from Richmond. "When you talk about people who were opposed to integration, you'd find a lot of people at that time who were. There's a lot of Lanes out there. But one of the most important things that can happen to an individual is when he gets religion, gets converted because then he can see both sides."

The man said Lane assured him he now supports racial equality.

Davis noted that Lane has received the endorsement of the influential Crusade for Voters, a black political group. "Use your head," Davis said. "Lane was head of the (House) Appropriations Committee which was in charge of giving out money to black state colleges. If you run around hollering about somebody's record on segregation all the time you're not gonna get anything. You play the game like it's been played on us. The game of politics is to use your political head and not your political heart.

"Both he and another convention delegate spoke of the first time they were asked to endorse House Majority Leader James M. Thomson of Alexandria who was a major figure in the development of the massive resistance legislation and whose sister is married to U.S. Sen. Harry F. Byrd Jr.

"I remember how hard it was for us to take Jim Thomson, the man said, "but if you look at his votes in the last few years he's really turned out ok. He supported public employee bargaining and now he's the majority leader."

Earlier in the day convention delegates heard Democratic State chairman Joseph T. Fitzpatrick refer obliquely to the same issue. He reminded the delegates that "we've had a difficult time getting black judges in Virginia" and noted that Republicans had voted against both blacks that he had nominated in the General Asembly, Judge Lester Moore and the recently selected Joe Jordan, both of Norfolk.