President Reagan, in a congratulatory call to the Redskins yesterday after their 31-17 victory over the Cowboys, asked them to give him a hand in dealing with Congress, implying the political task was easier than their feats on the football field.

"I just want to congratulate (you) and all that great gang of yours. What an afternoon this has been!" Reagan told Coach Joe Gibbs.

"Well, listen, I just wanted to say if the fellows feel like, when the season is over, letting down easy, I could use them helping me up there with the Congress."

The call was placed from Aspen Lodge, the president's quarters at his Camp David, Md., retreat. Reagan spent the weekend there working on his State of the Union address, but took time to watch the NFC championship game.

Mark Weinberg, assistant White House press secretary, said Reagan also called Cowboys Coach Tom Landry. Weinberg said the president told Landry to tell his players that "none of you have anything to be ashamed about. That's for sure."

Gibbs told Reagan: "This has been a team effort here, as you know. Everybody in Washington deserves the credit. Everybody."

Reagan, who played football in high school and college and the role of George Gipp in the movie "The Knute Rockne Story," told Landry, "I know there aren't any words that can make you feel any better because I guess I played in more losing games when I was playing in school than I did in winning ones and I know that feeling."

"But I just wanted to say, by golly, you're still there with a lot of class, you and that whole team," the president said, adding: "It was a great game. I won't say you haven't got things to be sorry about."

Landry responded: "We appreciate your calling us . . . because it was a great Redskins' day and you have to give the victors the accolades.

"They did a great job against us and of course you and I know we lose one every once in a while. We lost it now and of course we're hoping we'll be back again."