Congress will not pass the Kemp-Roth tax-cut plan even if President-elect Reagan pushes the measure, according to the outgoing chairman of the House Ways and Means Committee.

Rep. Al Ullman (D-Ore.), who was defeated in the November elections, told reporters he believes Reagan may change his mind both on Kemp-Roth and on a proposal to index tax brackets by tying them to increases in inflation once he takes office and is faced with high inflation and high interest rates. But if "they do make the mistake of recommending Kemp-Roth, the Congress is going to have to bail them out."

Ullman is almost certain to be succeeded by Rep. Dan Rostenkowski (D-Ill.), who yesterday announced his candidacy for the chairmanship of the committee. Rostenkowski had to choose between the committee chairmanship and the third-ranking leadership position of majority whip.

Rostenkowski in announcing his decision said, "As has become increasingly clear from the delayed timing of the announcement, this has not been an easy decision for me to make." He went on to say that the task of the Ways and Means chairmanship will be "not so much to advocate party position but to seek a workable consensus on issues that will be in the best interest of the people of this nation."

He gave no hint of what he planned to do as chairman but said that he stood "ready to assist" President-elect Reagan "where I am able and to disagree with him where I must."

The Oregon congressman praised Rostenkowski and said that he had no worries about the committee because it will have good leadership and good membership in the new Congress. His successor has been thought fonder of politics than of the nitty-gritty of tax-writing, but he is an experienced member of the Ways and Means Committee.

Ullman noted that the House would have to assert its prerogative for writing tax legislation to make sure that the major tax legislation billed for next year originated in the House and not the Senate. This year the Senate Finance Committee seized the initiative when House Democrats agreed with President Carter that there should not be an early tax cut and wrote a $39 billion tax-cut bill.

Ullman said he expects the House to begin action on a tax bill by March. There have to be tax cuts to boost investment and savings incentives next year, and there probably also will be "general relief for taxpayers," he told reporters. However, Ullman did warn that if inflation is running at 15 percent to 20 percent next year -- which he claimed is a real possibility -- then the new administration may have to declare a national emergency and hold off on its tax cuts.

Asked whether he foresees a Republican majority in the House after 1982 Ullman said that it is a possibility. The Republicans, and conservative groups backing them, ran a well-organized campaign this year and succeeded in defeating many Democrats, such as himself, Ullman pointed out. The Democrats have to restructure the party and recognize that it can't win based on "old issues and old ideologies."

Ullman also predicted a shift back to the old power structure in Congress where the speaker and committee chairmen hold the strings, rather than party caucuses.