WASHINGTON (AP) _ Ronald A. Pearlman, a former assistant secretary of the treasury, was appointed Monday as chief of staff of Congress' Joint Committee on Taxation.

In that role, Pearlman, 47, will head a group of lawyers and accountants that provides professional advice to the House and Senate tax committees. He succeeds David H. Brockway, who resigned to join a Washington law firm.

Pearlman was appointed by Sen. Lloyd Bentsen, D-Texas, and Rep. Dan Rostenkowski, D-Ill., chairmen respectively of the Senate Finance Committee and the House Ways and Means Committee.

''Mr. Pearlman's knowledge of the legislative process, his regulatory expertise and his extensive experience as a tax practitioner make him an ideal choice for this position,'' Bentsen and Rostenkowski said in a statement.

Pearlman, a graduate of Northwestern University and Georgetown University, has 17 years' experience in private law practice. His most recent government job was as assistant secretary of the treasury for tax policy.