First Lady Rosalynn Carter, declaring that her husband is fit to "lead our country through this time of crisis," today appealed for black support for her husband's embattled administration.

In a speech before the 69th annual convention of the National Urban League, she reeled off the names of many in the administration who she said, "happen to be black."

Afterward, the first lady plunged into the luncheon audience of about 1,000 conference participants, shaking hands, giving greetings and plugging "Jimmy."

But the speech, which many convention participants later termed a "disaster," may have undermined Mrs. Carter's effort to garner support from this group, the wealthiest and one of the most influential civil rights groups. Many of the delegates, however, said the blame did not lie with Mrs. Carter but with whoever wrote the speech and advised here to give it.

Most of the comments focused on what the critics said were "shallow" and "insulting" references to individual achievements rather than to long-term goals of blacks in America.

For example, in an almost sing-song fashion, Mrs. Carter said:

"We have added more than eight million new jobs. One million of those have gone to blacks. ...our major job programs have been directed in the Labor Department by the administrator of our CETA program. His name is Ernest Green. He happens to be black.

"We have a strong and dynamic woman in charge [of the Equal Employment Opportunity Commission]. Her name is Eleanor Holmes Norton. She happens to be black.

"There is no racial discrimination in the Army. We have an outstanding gentleman as secretary of the Army. His name is Clifford Alexander. He happens to be black."

Over and over again, Mrs. Carter repeated the "happens to be black" refrain. People began chuckling and snickering at their tables. Mrs. Carter joined in laughter when she made some favorable comments about Urban League President Vernon F. Jordan, who was sitting near her, and pointed out that he, too, "happens to be black."

The comments after the speech came swiftly. Most of those making negative remarks requested anonymity. Some examples:

"The speech points out what a lot of people have been saying - that the Carter admisistration doesn't really have the sensitivity to deal with people," said a white delegate.

"I've been trying to be a believer in and a supporter of this administration, but they surely make it hard," said a black woman conference participant.

"They've really set Kennedy up for tomorrow, didn't they?" said another black delegate. Sen Edward M. Kennedy (D-Mass.) is scheduled to address the group Monday.

Not all the reaction was negative.

"I thought it was a low-keyed speech, an honest attempt to emphasize that Carter has done well by blacks," said Ron Edwards, a Minneapolis utility company executive. However, he added: "She didn't have to say "happens to be black" so many times."

After speaking, Mrs. Carter received polite applause, noticeably less enthusiastic than she received when she came in.

The speech was the thinking and writing product of six people, according to Mary Hoyt, the first lady's press secretary.

League president Jordan said after Mrs. Carter's remarks that he appreciated her attempt to show that the Carter administration was doing something for blacks. But he said that "much more needs to be done," and that individual appointments are not enough to solve what he called major economic and social problems facing black America.

In a news conference before Mrs. Carter's speech, Jordan criticized Carter for the manner in which he fired members of his Cabinet last week. The league president said that Carter should have acted more swiftly and directly in dismissing his top aides to help alleviate "the agony of waiting" they and the nation endured. CAPTION: Picture, Mrs. Carter accepts award for her "dedication to human concerns" from Urban League official Juanita Wright.AP