The Reagan White House is moving on a new plan to blur its differences with blacks that involves both assailing established black leaders as salesmen of failed policies and appealing to the black middle class on grounds that it can greatly benefit from the Reagan agenda.

Early signs of both sides of the offensive were visible last week, first when the president met with black businessmen and academics to discuss possible government spurs to investment in black communities, then on Friday when he surprised even his aides by saying in an interview that he sees no value in talking to current black leaders because their main interest is to stir up their troops and hold onto their "rather good positions" instead of hearing his proposals for solving social problems.

"There are two ways to approach blacks after a victory of the magnitude we had," said a White House adviser. "One is to say the heck with them, and the other is to say it's an opportunity for a cease fire.

"The blacks took their best shot at us, nine of 10 voted against us, and we won easily . . . . We can say come join the winners now. Forget leaders from another time who don't have any new ideas, who lost this year and who are going to lose in 1988."

The administration plan, according to White House officials, is to show black leaders to be a group without muscle in either party at a time when many Democrats are saying that their party needs to play down connections with blacks and appeal to whites. Meanwhile, the officials said, the administration plans to emphasize the "common ground" where Republicanism can benefit blacks.

A secondary reason for the drive, some officials said, is to play down blacks as the central symbol in the "fairness" argument -- concern over the impact of budget cuts on the poor -- as the budget negotiations between the White House and Congress continue.

According to a strategy memo prepared for Reagan by James W. Cicconi, a special assistant to the president in Chief of Staff James A. Baker's office, the administration could send its message to that audience through proposals such as lower minimum wages for youths to help decrease black unemployment; renewed support for enterprise zones to rebuild black neighborhoods; housing vouchers to allow the poor to shop for housing; and increased assistance to crime victims, who most often are blacks in crime-ridden areas.

The administration plans to start its work with blacks by appealing to receptive pockets of black Americans, mainly business people. It expects that inroads made with that group will spread to professional and middle-class blacks who may be beneficiaries of the economic recovery and thus inclined to support the president except for their racial loyalties.

Administration officials believe that enough blacks are in middle-income brackets to provide a target audience for their appeal, and that the audience is influential enough to start reshaping blacks' opinions about Reagan and the GOP.

In 1983, of about 7 million black families, 1.8 million, or more than one-fourth, had incomes of more than $25,000 a year, which was roughly the median income for American society as a whole.

"We want to segment the black community essentially the same way we segment the rest of America," said Steven J. Rhodes, assistant to the vice president for domestic policy. "You wouldn't see the president going out to talk to liberal white women , so why should he go to the Urban League and the NAACP where we know we can't agree. We don't get anything from those groups but grief so why give them a platform. What we want to do is identify groups with the same preferences."

Rhodes said administration officials might speak to groups of black insurance agents, morticians, and bankers, or address economic problems at a black business school to reach the targeted audiences.

The response to the unveiling of the White House strategy has been skeptical. Eddie Williams, head of the Joint Center for Political Studies, which focuses on blacks and politics, said the White House is correct when it argues that there is a potential audience among conservative blacks.

But Williams said they are wrong in underestimating black concern about civil rights. He said an August Gallup poll showed that 72 percent of blacks, along with 31 percent of whites, see Reagan as "prejudiced."

"This is what white racists have done from time immemorial; they try to pick black people's leaders for them . . . ," said Roger Wilkins, a former assistant attorney general.

"They don't see themselves and their strategies as racist because they're willing to sit down with black businessmen," said Rep. Ronald V. Dellums (D-Calif.) "But they're not so quick to sit down with the poor and the hungry . . . . "