White House special trade negotiator Robert S. Strauss said yesterday that President Carter has "serious political problems" at home, and said he plans to join Carter's campaign effort this fall to help in the 1980 primaries.

At a breakfast meeting with reporters, Strauss said Carter and his aides "have a good deal to do before 1980 in repairing some of the damage... in traditional Democratic constituencies," such as blacks, labor and Jews.

Strauss said that while Carter's Middle East trip may help now, inflation will be the issue in 1980. "I think he'd better come right back and sit down and figure out how to make something cost less," he said.

Strauss said the White House soon will announce the appointment of "another bright, attractive young" Texan to help Democratic Party Treasurer Evan Dobelle as Carter's campaign chief and that he wouls sign on sometime this fall.

The Dallas Times Herald reported yesterday that John Dalton, a 37-year-old Texas investment banker, has resigned as president of Government National Mortagage Corp. and will become treasurer of Carter's campaign.

The newspaper also reported that Tim Smith, a 30-year-old attorney who was deputy appointments secretary to Carter before tranferring to the Justice Department to work as an antitrust lawyer, will be named deputy campaign manager of the Carter committee's legal affairs.

[Dalton confirmed that he has submitted his resignation as head of the government mortgage agency, effective Monday, and said he would be associated with Carter's reelection drive starting next week, the paper said.]

Strauss, former chairman of the Democratic National Committee, said he probably will serve without title, and that, if there is "any unique contribution I can make, it will be in the primary" season.

He said he plans to leave the government this autumn, presumably after Congress completes consideration of the multilateral trade agreement that Strauss and his aides have negotiated.

The pact, which is proving to be controversial, is to be signed and sent to Congress next month, Strauss said. He warned that "there will be no concessions made" to domestic pressure groups.

Strauss made his comments during a free-wheeling session in which he acknowledged that Carter is in trouble in the polls and will have to wage a strong fight in the 1980 primaries.

He attributed the situation to "a failure on the part of many of us to properly articulate to these groups what the president has done for them." Later, he said, "Primarily, the responsibility is the president's. He has not done well."

Strauss said the Carter campaign staff also will include Atlanta lawyer Charles Kirbo and Lee Kling, now Strauss deputy, who will be finance chairman.

Strauss dismissed the prospects of serious challenges to Carter from Sen. Edward M. Kennedy (D-Mass.) and California Gov. Edmund G. (Jerry) Brown Jr. Of a Kennedy campaign, Strauss said he has "never heard anyone around" the senator "indicate he's going to get into it."

He also said he did not think Carter and his advisers could run the 1980 campaign like the 1976 campaign -- that is, without working along traditional Democratic Party lines.

He also conceded that "the farm community does present a problem" to Carter.But he predicted that farmers, and other groups, would come back into the fold "when they look at his record."