President Reagan made a surprise appearance before the potentially hostile delegates of the White House Conference on Aging yesterday to defend his efforts to solve the problems of the Social Security system and to deny that he is "somehow an enemy of my own generation."

The president said he would not raise taxes to shore up Social Security's shaky finances. That would leave benefit cuts as the alternative way to restore the system's integrity. But the president proposed major benefit cuts once this year and was forced to back down in the face of a storm of opposition--one of his few defeats this year.

This time Reagan referred instead to a tripartite, bipartisan task force he has set up to consider Social Security's problems, saying it will be that panel's responsibility to propose changes in the system.

Identifying himself at the outset as a member of the generation whose problems the conference is deliberating, the 70-year-old Reagan reaffirmed his 1980 campaign pledge not to "betray those entitled to Social Security benefits."

"I agree with what Congressman Claude Pepper D-Fla. has said, that this country is big enough and able enough to provide for those who have served it and now have come to their time of retirement," Reagan said. "What we can't afford is supporting, as disabled, people who are not disabled or educating from Social Security funds young people from families of affluence or wealth."

Reagan said the task force's charge will be "to work with the Congress and the president, not only to propose realistic, long-term reforms to put Social Security back on a sound financial footing, but also to forge a working, bipartisan consensus so that the necessary reforms will be passed into law." Reagan will name five of the panel's 15 members, and the Senate majority leader and House speaker will name five apiece.

Before Reagan's speech to the delegates at the Washington Sheraton hotel, which was carried by closed circuit television to those at the Washington Hilton, a key committee of the conference reflected the administration's position on Social Security by defeating a number of resolutions that run counter to it and adopting one that agrees with the administration's philosophy.

After the votes by the committee on economic well-being, which will make the bulk of the recommendations concerning Social Security to the conference's plenary session Thursday, leaders of key groups concerned with aging renewed their charges that the committee and others had been "stacked" with pro-administration delegates.

Reagan's 23-minute speech to the more than 3,000 conference delegates and observers was sprinkled with references to his own status as an aging American. His was not simply the traditional visit of a president to a White House conference, he said: "We have met to counsel together on matters of mutual interest."

A few moments later he made the point again. "Let me say a few words about us," he told the delegates.

Reagan received a warm reception from the delegates but not nearly as enthusiastic as that given Monday to Pepper, an honorary chairman of the conference, or to Arthur S. Flemming, a member of the conference's advisory committee and the man whom Reagan recently fired as head of the U.S. Civil Rights Commission. Flemming was seated on the dais while Reagan spoke.

In the economic well-being committee yesterday, delegates overwhelmingly approved a resolution opposing any use of general revenue funds to finance Social Security. The resolution was offered by Republican Bruce Nestande, an Orange County, Calif., supervisor and former Reagan aide. Nestande, 43, who was one of 400 delegates appointed to the conference within the last two months by the administration, was the first committee member to offer a resolution. His resolution, opposed by groups representing the elderly, carried 111 to 34.

By similar votes, the committee members killed a motion reaffirming the 1971 White House Conference's support for a national policy to raise the income level of retired persons to the Bureau of Labor Statistic's intermediate level--roughly $9,400 for a couple.

"I refuse to underwrite a program that is more beneficial to a person who happens to be on a little tough luck than it is for me," said Harry Doughty, a Social Security recipient and a delegate from California.

The delegates also rejected a resolution to remove the Social Security system from the unified federal budget. A resolution calling for removal of any mandatory retirement age carried by a voice vote. A separate resolution opposing any Social Security benefit cuts for current recipients passed overwhelmingly once it was amended to delete a reference to all workers now paying into the sytem. As amended, the resolution reflects the administration's position.

The committee began its deliberations by hearing from Robert M. Ball, the former commissioner of Social Security, who was specially invited by the committee chairman after he was not assigned to the committee. Ball told the committee members that "there's no great big disaster hovering over this system" and that it is "absolute nonsense and 100 percent poppycock" that the system's short-term financing problems have to be solved by long-term cuts.

Speaking last night at a meeting attended by more than 600 persons and called by the Leadership Council of Aging Organizations, Pepper agreed to lead a protest this morning at the economic well-being committee.

Referring to Nestande's resolution, Pepper said: "If that resolution is adopted by this conference, you have immeasurably hurt Social Security. You have immeasurably handicapped your friends in Congress trying to help Social Security. We must not allow that resolution to pass."