A rule change that would have forced a vote on the Equal Rights Amendment on the Virginia House floor was rejected by a 62 to 36 margin today, defeating what ERA supporters thought was their best avenue for approval of the amendment this year.

The amendment has been bottled up in the House Privileges and Elections Committee, where a majority of members oppose it, for the past four years.

Virginia is one of only two states that have failed to put ERA to a vote of the full legislative since it was proposed by Congress in 1972. The other state is Mississippi. Three more states must ratify the amendment by March 22, 1979 to make it part of the U.S. Constitution.

The ERA was approved Wednesday by the Indiana legislature after a last-minute phone call from Rosalynn Carter broke a deadlock in the State Senate.

The rule change that would have forced a vote on ERA by the House would have required that all proposed amendments to the U.S. Constitution to brought before the full House no more than 20 days after they are introduced.

The defeat was another bitter disappointment for ERA supporters who have fought for four years to get the Assembly to act on it. The size of the margin also surprised them. "It didn't jibe with our count before the vote," ERA lobbyist Norma Murdoch-Kitt of Richmond said.

The 79-member House Democratic caucus failed to endorse the change last week by only two votes, 36 to 34. Today, only 31 Democrats and five Republicans voted for the change, while 46 Democrats, 12 Republicans and all four Independents voted against it. Two Democrats who favor ERA and the rules change were absent.

Only two of 19 Northern Virginia House members voted against the rule change. They were Dels. James M. Thomson (D-Alexandria), the House majority leader and chairman of the Privileges and Elections Committee, and Wyatt B. Durrette Jr. (R-Fairfax), a candidate for the Republican nomination for attorney general.

Hopes were high among ERA backers for a different result because some delegates who have said they will not vote for the proposed amendment nevertheless say they believe every proposed change in the U.S. Constitution should come before the full House. Del. Donald G. Pendleton (D-Amherst), who introduced the rules change, told the House he will vote against ERA if it ever comes to a vote.

Reciting Virginia's record of frequently rejecting or refusing to consider constitutional amendments affecting civil rights. Penleton declared: "Virginia is known as the Mother of Presidents. From what I see, we may have gone through the change of life."

The next opportunity for a test on ERA will come on Monday, the deadline for introduction of bills and resolutions in this session. Motions may be made in both houses to bypass the Privileges and Elections Committees and put the ERA resolutions before each house acting as a committee of the whole.

This maneuver is given a fair chance in the Senate because P&E Chairman Omer L. Hirst (D-Fairfax) is an ERA supporter and has said he does not believe any purpose will be served by again referring the amendment to his committee. His committee killed it, 8 to 7, last year.

The House also acted on two other controversial rules changes today. By a vote of 62 to 35, it rejected a proposal by Del. Raymond E. Vickery (D-Fairfax) that would have barred House action on the annual budget bill until three days after it is reported from the House Appropriations Committee.

Some delegates have complained that the budget bill, after weeks of consideration by the Appropriations Committee, is pushed too hastily through the full House by the leadership. The current budget, which over-estimated state revenues by $220 million, as adopted after only about three hours of consideration last year. Most of the time was taken up with reading of complex committee amendments.

By a vote of 58 to 32, the House adopted another Vickery proposal prohibiting committees from excluding from their closed meetings any delegate who wishes to observe them. The Appropriations Committee, whose chairman, Del. Edward E. Lane (D-Richmond), has demonstrated a penchant for secrecy, has sometimes asked delegates to leave its closed meetings.