President Carter has begun an intensive lobbying campaign on Capitol Hill that includes deployment of his Cabinet, even at freshmen congressmen, in behalf of priority bills.

To start off the new campaign, Cabinet officials this week descended on dozens of members of Congress from both parties to seek support for reform of the federal bureaucracy - the issue that won Carter popularity and votes in 1976.

The legislature push is a direct outgrowth of a searching reassessment of the administration's record and techniques at Camp David, Md., on April 16.

There, Secretary of Agriculture Bob Bergland said yesterday, Carter attributed his decline in popularity to a "kind of fuzziness" in the public perception of his presidency.

Bergland's remarks to reporters at a Washington breakfast meeting provided clues to the president's mood and intentious as his popularity sinks to its lowest ebb.

According to Bergland, the "fuzziness" was attributed at Champ David to public confusion about "who is Jimmy Carter? What are his programs and policies?" Carter feels this public image is "fair," but "not the last word," Bergland said.

The agriculture secretary said the Champ David talks centered on analysis of mistakes and ended with agreement to sharpen the administration's image by focusing on specific, "priority" measures every two or three weeks.

White House spokesman Jody Powell said the intensive lobbying effort this week on reform of the civil service as the model for the administration's handling of other key measures, such as tax reform and energy.

Powell said the president personally gave each Cabinet secretary a list of members of Congress to contact on that issue by the close of business Tuesday. Another White House official said yesterday that by noon tomorrow, at least 250 House members would have been contacted on behalf of Carter's Plan to reshape the federal bureaucracy.

Secretary of State Cyrus R. Vance contacted 15 by Tuesday to plug for the measure.

The lobbying effort has given special attention to Republican members of the House PosT Office and Civil Service Committee. That committee's ranking Republican, Edward J. Derwinski (111.), and his party juniors were invited to meet Carter today on the civil service reform bill.

Derwinski said he was "sort of" surprised by Vance's call. "I thought he was calling about the F15 (fighter plane), which I don't support. When I heard him express his views on the need for civil service reform, I heaved a sign of relief."

Derwinski said he found the administration "incredibly unsophisticated - it's either underkill or overkill," he said.

Rep. Jim Leach (R-Iowa), a freshman member of the Civil Service Committee, said he was contacted by Treasury Secretary W. Michael Blumenthal and by Housing and Urban Development Secretary Patricia Roberts Harris regarding civil service reform.

"It was quite something," he said. "usually I have trouble enough getting access to low-level people in the bureaucracy." Leach said the contacts "symbolized the breakdown of Democratic leadership on the Hill."

The Associated Press reported yesterday that White House concern with ineffective performance resulted in two meetings between Carter insiders and veteran members of the Washington political establishment in February and March.

The two groups exchanged complaints about the way the administration was functioning, down to Carter's failure to authorize the distribution of photographs to congressmen as an economy move.

Mixing at one or both of the meetings were Powell, Hamilton Jorden, Frank Moore and Robert Strauss - the Carter men - and old Washington legal hands Clark Clifford, James Rowe, Lloyd Cutler, Harry McPherson and Lloyd Hackler, the news agency reported. The February meeting took place at Strauss' Watergate apartment, the second in March, at his office.

The full House committee is still holding hearings on proposed civil service reform legislation and the administration wants a bill reported out by May.

The administration proposal would increase the control over the bureaucracy by providing for new disciplinary procedures, incentive pay and other measures.