Prime Minister Margaret Thatcher has become personally involved in a new British attempt to restore some form of home rule to Northern Ireland under which the Protestant majority and Catholic minority could share power.

Thatcher has invited the leader of the three Ulster political parties represented in Parliament here to meet separately with her during the next two weeks to discuss efforts to combat IrisRepublican efforts to combat Irish Republican Army terrorism in the trouble province.

The Rev. Ian Paisley, leader of the Democratic Unionists, the most militant Protestant party, had demanded such a meeting with Thatcher before he would agree to attend a conference of Ulster political leaders to discuss new British proposals for limited home rule there.

Her agreement to meet with Paisley, thought by many to be the provience's most powerful politician, as well as the other parties, spurred hopes for the stalled British home-rule initiative.

While trying to stop sectarian strife in Ulster through direct rule, the British have been responsible for even such normally local matters as education, housing and health. Except for representing Northern Ireland in Parliament here. Ulster politicans have had little responsibility under direct British rule, a power vacuum widely believed to exacerbate sectarian tensions there.

The conference to which Ulster political leaders have been called by Thatcher's Northern Ireland Secretary, Humphrey Atkins, is to consider a wide range of British proposals, from giving Ulster's present local governments some real responsibility to creating some kind of provincial parliament.

Each of the proposals to be put before the conference, which is scheduled to begin in December, is to include what British officials describe as "reasonable and appropriate arrangements to take account of the interests" of the Catholic minority.

Gerry Fitt, leader of the Catholic Social Democratic and Labor Party, has reluctantly agreed to participate in the conference. James Molyneaux, head of the Ulster Unionists, has thus far refused to attend, but British officials believe he will change his mind.