George Meany, the 85-year-old one-time plumber who has been a symbol of the American labor movement for most of the 20th century, disclosed yesterday he will step down in November as president of the AFL-CIO.

The impending retirement of the ailing Meany was announced formally by his heir apparent, Lane Kirkland, 57, a close friend and ally who has been secretary-treasurer of the 14-million-member labor federation for 10 years.

Kirland's almost certain ascendancy to the AFL-CIO presidency at the federation's November convention is not expected to produce major policy changes. But he is expected to offer more vigor and flexibility at a time that the labor movement's fortunes are in economic and political decline. Unions' share of the work-force is declining, and they complain that their share of the political action is shrinking as well.

Asked if he would seek the presidency, Kirkland said, "Yes." Asked what challenges the job will entail, he said, "Everything."

Kirland, speaking in almost reverential tones, told a news conference that Meany informed him of his decision Thursday night and asked that it be conveyed to the AFL-CIO executive council as it met yesterday to endorse an economic "accord" with the Carter administration.

Meany, who had been incapacitated for most of the year with knee and hip ailments, was reportedly ill yesterday with intestinal flu.

While it has been expected for years, Meany's retirement strips the national stage of one of its premier actors: a gruff, cigar-chomping caricature of a labor leader who outlasted most of the presidents, members of Congress and captains of industry who tangled with him during his 69-year labor career.

He rose from plumber's apprentice in the Bronx to head of the New York labor federation and came to Washington in 1939 as secretary-treasurer of the American Federation of Labor, becoming confidant to and critic of presidents from Franklin D. Roosevelt to Jimmy Carter.

Meany was a key figure behind the merger in 1955 of the once-feuding AFL and Congress of Industrial Organizations (CIO), and became its first -- and thus far only -- president.

He was a consolidator rather than an innovator, a full and demanding partner in the capitalist system, a crusty debunker of the ideological concerns that characterized the labor movements of many other countries, and he had an ample share of detractors, both in and out of the labor movement. Many, even friends, believed he stayed beyond his time. But, characteristically, he went out in a time and style of his own choosing.

Kirkland, an intellectual, soft-spoken former merchant seaman whose differences with Meany are more of style than of substance, is regarded as a shoo-in as his successor at the AFL-CIOs biennial convention here in mid-November.

But there is the possibility of a serious challenge to Kirkland after two years if, as some belive, Meany's departure unleashes forces and ambitions that have been suppressed over the years by Meany's dominating presence.

There is also a possible contest for the No. 2 job of secretary-treasurer that Kirkland will be vacating. Thomas Donohue, Meany's top assistant, is favored by some but opposed by others who argue that at least one of the president, a representative of the building trades, or both. Plumbers President Martin Ward, Operating Engineers President J.C. Turner and Robert Georgine, head of the Building Trades Department of the AFL-CIO, have been mentioned as potential candidates.

In any case, the AFL-CIO no longer will be a one-man show, probably meaning new ideas, new alliances and more new people. One union president yesterday described Meany's retirement as a "watershed" event for the labor movement, but said he couldn't predict where it would lead.

Asked what the labor movement will be like without George Meany, Kirkland said it has a "sound foundation" and added: "I don't think George Meany ever regarded himself as an indispensable man."

Kirkland, Meany's clear choice as successor, made his debut in a way that may foreshadow a Kirkland style of leadership, pushing through consensus rather than through confrontation to steer a reluctant government along labor's chosen path, in this case involving economic policy.

But he also made it clear he would use labor's favorite sanction -- the walkout -- if the administration fails to live up to the broad economic policy goals they embraced in their "national accord."

This kind of "American adaptation," as Kirkland called it, of the European-style social compact between labor, business and government, appeared to be largely his doing. It is clearly a more innovative approach than the country has come to expect from the AFL-CIO in recent years.

It also is considered possible that Kirkland's ascendancy may bring the independent United Auto Workers and possibly even the International Brotherhood of Teamsters, with a combined membership of about 3.5 million members, back into the AFL-CIO fold, Kirkland has said he would welcome them back. The UAW flirted with the idea of a couple of years ago but shelved it, partly because of old differences dating back to Meany's feuds with the late UAW president, Walter Reuther.

Kirkland said Meany gave him no reason for stepping down now, but most of his colleagues believed the Meany, despite continued mental acuity, lacked the physical strength to keep going.

He was hospitalized last April with complications from a knee injury suffered in a golf cart accident, aggravating a recurrent hip problem and sapping his strength. Although he has not been seen in public for five months, people who have seen him say he has aged visibly and moves about mostly in a wheelchair. Eugenie Meany, his wife of nearly 60 years, died last spring.

Kirland said Meany would attend the federation's November convention but would not permit his name to be submitted for reelection. Kirkland is the only avowed candidate for the two-year presidental term.

As presidents of most of the federation's big unions and scores of AFL-CIO employes crowded the news conference room to hear Kirkland's announcement, Kirkland said, "There is so much I feel I want to say. . .I cannot say anything." His voice quavering, he said the council had expressed its "deep love and respect for this great man . . . who represented the rights and interests of plain people in this society."

Tributes quickly began to pour in to the AFLC-CIO headquarters, from old foes as well as friends.

Heath Larry, president of the National Association of Manufacturers, said Meany had his differences with American business but "they were always articulated openly and with rectitutde [and] we salute him and wish him well."

President Carter, whose relations with Meany were often chilly, told reporters at a briefing on the economic accord that the nation benefited from "his heart, his mind and his experience." Vice President Mondale said Meany's name has been "synonymous with decency, social justice and the dignity of American workers."

UAW President Douglas A. Fraser acknowledged he and Meany had some differences but said, "Millions today are enjoying a better life because George Meany was there to fight the good fight for them."