A compromise agreement on reforms of the U.S. Postal Service, including presidential appointment of the Postmaster General, was scheduled last night for a vote in the House next Thursday.

According to Rep. James M. Hanley (D-N.Y.), chairman of the Postal Operations and Services Subcommittee, the legislation will go before the Rules Committee on Tuesday.He forecast "Overhelming approval" by the full House.

The new legislation represents an attempt at compromise between congressional leaders and the Carter administration, which had opposed earlier bills because of heavy additional postal subsidies.

The revised Postal Service Act of 1977 will not be supported by the administration. However, a congressional aide said the White House won't oppose the bill, either.

As bow drafted, the legislation includes the following major provisions:

The president would appoint the Postmaster General for fixed, four-year terms. Since the old Post Office Department was transformed into an independent agency at the start of this decade, a Board of Governors has selected the service's chief executive.

The Board of Governors would remain in existence with a chairman appointed by the president and an independent staff.

The current $920 million annual subsidy would be extended to 1984 and an additional $80 million a year until 1981 would be provided - half the proposed increase in annual subsidies proposed earlier.

The Postal Rate Commission would continue to have final authority to establish postal rates without congressional review, sought earlier by some House members.