In the most heated confrontation of the campaign, Prince George's County Executive Winfield M. Kelly Jr. last night accused his Republican opponent, Lawrence J. Hogan, of repeating "a pattern of charges that he knows are not true" and "promising to give everything to everyone."

Kelly, sitting only two feet away from Hogan during a debate taping at WTTG-TV, at one point looked his opponent in the face and said, "The basic issue is his (Hogan's) credibility." This accusation marked the first time that Kelly, normally a mild-mannered and subdued politician, has so aggressively attacked Hogan in the county executive's race.

The county executive charged that Hogan was "simply wrong" in his oft-repeated claim that the county's police budget includes $3.4 million for purchasing administration. Kelly said the money in fact was applied toward the purchase of uniforms, gasoline and auto repair.

"I think you can't talk about things that aren't honest," said Kelly. "If you keep telling people things that aren't ture, Larry, you're going to have to live with it later."

Hogan, whose own polls show him holding a substantial lead over Kelly, appeared stunned by his opponent's strident attack. "I don't know what got into Winnie in there," Hogan said after the debate. "Never in my life have I seen him act like that."

For his own part, Hogan accused Kelly of "out and out lying" during the debate when the county executive claimed that he did not support all of the taxes that Hogan said he did, a tax list that included a 1c sales tax increase, a state tier tax, an apartment tax, and taxes on dogs and cats.

An another television debate last week, Kelly did not challenge Hogan when the former Republican congressman pulled out typewritten list of about 20 taxes that he claimed Kelly supported.

"I wasn't going to let him get away with that again this time," Kelly said after the debate. "There are some taxes on Hogan's list that I never supported or intended to enact."

Kelly said that every tax proposal has made during his four years in office has been part of an effort to "move away from the most archia, fair tax ever levied - the property tax." As he does no every political occasion, Kelly noted that the average county taxpayer received a $100 property tax cut in 1978.

Hogan, in response, said that Kelly should have used all of a $20 million surplus this year to effect an even larger tax cut. "The only question the individual Prince George's citizen should ask," said Hogan, "Is whether he is paying more taxes now than he was four years ago."

For the last week, Kelly and his aides have been unable to conceal their anger about what they believe to be Hogan's calculated effort to distort the facts. "I've become convinced that Hogan will say anything to anybody," Kelly said before the debate. "It's my job to stop it right now."

Kelly, in an interview yesterday, said he was particularly upset by Hogan's frequent charge that most of the new businesses that have located in the county since 1974 actually were lured there by Kelly's Republican predecessor, William Gullett.

During last night's debate, Kelly pulled out a list of corporate executives whom he said would be happy to testify publicly that it was Kelly, and his "New Quality" economic development program, that persuaded their companies to move to Prince George's County.

Hogan argued that Kelly's economic development program was only successful at attracting "warehouses, fast food shops and massage parlors."

The intensity of last night's debate was such that Kelly and Hogan kept yelling and arguing with each other during every commercial break. The two men, who often have said that they are personal friends, did not speak to each other after the debate.