The White House said yesterday President Reagan is ready to veto banking legislation about to emerge from Congress, while the outgoing chairman of the Federal Reserve Board urged that the bill be signed.

"I think the bill has some parts I would prefer not to see, but overall, it is a constructive piece of legislation," Paul A. Volcker said in questioning before the House Banking subcommittee.

Volcker, who sought to keep in check the powers of banks throughout his eight-year tenure at the Fed, said the failure of Congress to pass banking legislation that reflected changes in banking technologies and markets was his biggest disappointment as Fed chief.

"In some respects, we have moved backward," said Volcker. "I leave with some hope that maybe this current bill will break the logjam."

In an unusual move, Volcker also took the opportunity to criticize the Federal Home Loan Bank Board for not being objective enough in its regulation of U.S. savings and loan institutions. He said he respected Edwin J. Gray, who has just departed as bank board chairman, but that board actions in the past helped create some of today's problems within the thrift industry.

"The Home Loan Bank Board has been insufficiently independent of the industry it regulates," Volcker said. He accused the bank board of issuing "popular" regulations that contributed to the savings and loan crisis.

Large segments of the banking industry are experiencing their worst times since the Depression, with bank closures on a constant upward curve since 1980. The savings and loan industry also has been hard hit, with 20 percent of those institutions operating at a loss.

In that environment, Congress has crafted a broad compromise banking bill that in effect would stall deregulation of the banking industry. The Reagan administration has strongly supported deregulation.

Calling further negotiations on the current bill "pretty hopeless," White House spokesman Marlin Fitzwater said yesterday that the president is ready to veto the legislation.

Fitzwater said the administration viewed the measure as "a very bad bill, unacceptable in every respect."

The legislation would halt the creation of new "nonbank banks" and places a March 1988 moratorium on the underwriting of new securities and other services by banks.

It also offers far less in borrowing authority for the insolvent Federal Savings and Loan Corporation than the administration says is necessary to address the troubles of the savings and loan industry.

Volcker predicted banking legislation would be among the major issues incoming Federal Reserve Board Chairman Alan Greenspan will face when Volcker leaves the job on Aug. 6.