President Reagan made a sentimental visit to old conservative friends last night and asked them to join him in a "new crusade" against "sob-sister critics" of his administration.

Speaking before the friendliest of audiences, the Conservative Political Action Conference, the president pleaded with restless allies to stick with his defense and economic programs, reminding them, "We have come a long way together.

"We are standing by our program, we will not turn back or sound retreat just as we near victory," Reagan told the conference, which he has addressed in seven of the nine years of its existence.

Despite the victories of the last year, the president said, "We must not become too comfortable with our newfound status." Later, he added that Washington remains "a company town. And the company's name is government, big government.

"In the discussion of federal spending, the time has come to put to rest the sob-sister attempts to portray our desire to get government spending under control as a hard-hearted attack on the poor people of America," he said.

Reagan compared critics of his projected budget deficits with "a dog sitting on a sharp rock howling with pain when all he has to do is get up."

The crowd of 1,300 at the Mayflower Hotel included seven Cabinet officers, seven Republican senators, several congressmen and a host of administration appointees. Reagan's speech was interrupted 25 times by applause.

It was, said Rep. Mickey Edwards (R-Okla.), chairman of the American Conservative Union, a "Reagan love feast, and it ought to be."

The president laced his remarks with symbolic references to conservative stalwarts such as President Coolidge and writer Russell Kirk and conservative publications such as the National Review and Human Events.

A year ago, before the same gathering, Reagan used many of the same references.

But this year his remarks were more defensive. He seemed more anxious to rally the troops to new victories in elections than to congratulate them on what has been accomplished. He set up his theme for the year in doing so.

"I have no intention of leading the Republican Party into next fall's election on a platform of higher taxes and cut-rate defense," the president said.

If Democrats want to run as "the party that refused to cut spending" and the "party that tried to take away your tax cuts," Reagan said, "we'll give them all the running room they want."

The president's appearance came amid increasing uneasiness among conservatives about budget deficits, his foreign policies and appointments to his administration.

It came hours after Conservative Digest, a publication owned by New Right direct mail expert Richard A. Viguerie, released results of a poll of conference delegates. They gave his administration a "D" grade on appointments, a "C" for abandoning the goal of a balanced budget and a "C" on its commitment to the so-called conservative social issues of abortion, busing and prayer in schools.

Reagan devoted only two paragraphs of his speech to these social issues. "This administration is unalterably opposed to the forced busing of school children, just as we also support constitutional protection for the right of prayer in our schools," he said.

On abortion, the president said, "We must with calmness and resolve" persuade other Americans that abortion "amounts to a great moral evil, an assault on human life."

The speech was part of an all-out administration effort to woo conservatives at the conference. Nine Cabinet members are scheduled to appear before the gathering, sponsored by Young Americans for Freedom and the American Conservative Union.

Reagan pointedly asked conservatives to "join me in a new effort, a new crusade," reminding them that "changing habits of four decades is going to take more than 402 days."

Reagan was notably silent on specific issues of concern to many conservatives. He did not mention allegations that his administration is staffed by large numbers of "non-Reaganites."

Nor did he allude to specific congressional attempts to amend the Constitution to ban abortions or define life as beginning with conception.