A former high-ranking official at the Small Business Administration during the Carter administration has been cleared of all charges that he tried to use a nationwide job transfer plan to get rid of SBA district directors who were Republicans.

The U.S. Merit Systems Protection Board, established under the 1978 Civil Service Reform Act to protect government employees from political manipulation and other types of job discrimination, said in a 32-page written opinion issued this week that "the evidence simply did not establish that Paul D. Sullivan targeted district directors for transfers because of their political affiliations.

The charges were brought to the board in July 1980 by its former acting special counsel, Mary Eastwood, whose office is authorized by Congress to investigate and prosecute allegations of improper personnel practices in the civil service. It was the first disciplinary case brought before the board by the special counsel's office, which recommended that Sullivan be dismissed from his job and fined $1,000.

The special office contended that the SBA's plan to rotate district directors was "a sham having no legitimate purpose'' and labeled the policy "the latest addition to an established record of political intrusion into personnel matters at the SBA," and board said in its opinion. But, the board said, Eastwood failed to produce any evidence to support those contentions.

Sullivan said in a telephone interview yesterday that he felt "vindicated" by the board's decision, but added he also felt "a little dirtied" by the long process that finally ended with dismissal of the charges against him.

Sullivan was associate deputy administrator for support services, the third highest post at the agency, and had been executive director of the Democratic National Committee before he came to the SBA in August 1978. He resigned his job effective Jan. 20 with the inauguration of President Reagan.

The three-member merit board said that Eastwood had presented them with "largely circumstantial evidence that left us with the sense that she had mistaken smoke for fire."

The board, which conducted an 11-day hearing into the allegations in January, said that because of Sullivan's "consistent and unshaken testimony that he had legitimate reasons for his actions and the ample amount of corroborating evidence," it was compelled to conclude that Sullivan had not committed any violations.

When the plan was implemented, the SBA ordered that 17 district directors, 15 of whom were Republicans, be transferred to other geographical areas. Seven of the district directors resigned from their jobs or accepted other jobs instead of accepting transfers to new locations.

Sullivan did not deny that he inquired about the political affiliations of the district directors who were suggested by SBA regional administrators for inclusion in the rotation plan. But he contended he did so in order to determine what political fallout might result from the transfers, not to target Republicans.

The board noted that Sullivan's former special assistant, Lawrence Hemphill, testified in the hearings that Sullivan told him that Republican district directors would be moved. However, the board said that it could not give any weight to Hemphill's testimony since earlier he said in a sworn statement and told an investigator for the special counsel's office that he did not know why the district directors were being rotated.

Hemphill resigned from the SBA in March 1980, five months before the charges were brought against Sullivan, after the SBA inspector general's office investigated charges that he had falsified various documents, including his SBA job application. The merit board said Hemphill later admitted the charges.