Marriner S. Eccles, 87, a millionaire who formulated many of the fiscal policies of President Franklin D. Roosevelt's "New Deal," died last night at his home is Salt Lake City.

Mr. Eccles made his contributions from the chairmanship of the Federal Reserve Board and then of the Federal Reserve System, guardian of the nation's money supply.

He held those positions from 1934 to 1948. After relinquishing them, he remained a memeber of the board until 1951.

At the core of Mr. Eccles' views was the conviction that money and credit should be used for social purposes.

To promote these purposes, he concentrated on two themes: The government must spend and go into debt in times of depression. It must tighten credit and reduce its borrowing and spending in times of inflation.

In advancing these ideas, Mr. Eccles was on the leading edge of the economic thought of his time. He advocated deficit financing before the theories of the British economist John Maynard Keynes became widely promulgated. Even at the outset of World Warr II he saw inflation as a threat to the economy.

He was an early and vociferous opponents of U.S. involvement in Vietnam, and blamed the nation's economic difficulties of the past 10 years on that war.

Many of these policies were anathema to the business community.

Yet Mr. Eccles was a businessman himself and an entrepreneur in the classic mold. Born to wealth, he came into control of this inheritance at the age of 22 when his father died and used it to build one of the great fortunes in banking, construction, sugar beets and other enterprises.

He once said that his chief preoccupation until the stock market crash in 1929 and the onset of the Great Depression was making money. After that, by his own account, he turned his attention to the American economy, and how to put it back on its feet.

He expressed his ideas in testimony before the Senate Finance Committee in 1963 shorty before Roosevelt's first inauguration.

He proposed increased government spending. he called for higher income and inheritance taxes, for unemployment benefits, for government control over securities and stock exchanges, and for cancellation of war debts. He called for child labor laws and for social security, for regulation of the banking system and federal control over transportation.

These recommendations came from a man who was proprietor of a number of banks in Utah and esewhere in the West when the crash came in 1929. None of his banks failed. No depositor lost a single dollar.

With the exception of war debt cancellation, all of his recommendations became part of the New Deal.

Despite charges that he had betrayed the business world, Mr. Eccles remained a businessman.

"The main concern of the American economy must be to assure maximum employment to its members," he wrote in 1934. "Under capitalism, private enterprise must be the main means to this end. Government can and should insist on minimum standards of decency in the mode and conditions of life for its people . . . But in the final analysis, these must under capitalism, be enforced and supported by the productivity of the business community itself.

Marriner Stoddard Eccles was born in Logan, Utah, Sept. 9, 1890. His father, David Eccles, was born in Scotland and moved to the United States in the 1860s. The family was converted to the Church of Jesus Christ of Latter Day Saints, and settled in Utah. Marriner Eccles was the oldest son of his father's second wife and one of 22 children.

He was educated in Logan and later attended Brigham Young College. In 1909, he went abroad as a millionary for the Morman church. He met May Campbell Young in Scotland, and they were married in 1913. The marriage ended in divorce in 1948 and Mr. Eccles married Mrs. Sara Madision Glassie of Chevy Chase in 1951.

Mr. Eccles began to take over his father's considerable business interests by the time of his first marriage. In 1916, he organized the Eccles Investment Co. and in 1927 the First Security Corp., a bank holding company. He also organized the Utah Construction Co., one of six firms that built Boulder Dam, and several other businesses.

It was with this background that he began to ponder what made the economy work. In 1933, he made a speech in Logan in place of Stuart Chase, a noted economist, who had been delayed by a blizzard. Chase heard the end of Mr. Eccles's remarks and advised him to go to Washington.

In 1934, President Roosevelt appointed Mr. Eccles special assistant to Henry S. Morgenthan, the Secretary of the Treasury. A few months later, Roosevelt named him to the Federal Reserve System. IN 1939, he became chairman.

One of Mr. Eccles' first acts after joining the board was to call for more stringent supervision of the nation's banks. One of the first pieces of legislation in which he played a major role was the Banking Act of 1953, which gave the board greater powers over money supply and credit. The purpose of these powers was to enable it to deal more effectively with economic crises.

During World War II, the Treasury Department, not the Federal Reserve System, was in control of the nation's fiscal anc credit policies. As the war gathered momentum, Mr. Eccles began urging steps to ease the upward pressure on the prices of war-scarce goods.

He initiated limits on consumer credit. He also supported the War Bond program. One of the reasons for this was that the bonds - about $40 billion worth of which were sold during the war - soaked up consumer dollars, easing the pressure on prices.

Mr. Eccles believed savings bonds would provide a measure of security for many persons through what was expected to be a period of recession and unemployment as the war economy ground down. At the same time, he believed, the bonds would serve to "prime" the economy as holders cashed them in and spent the money.

But no depression materialized. The economy kept expanding and inflation grew. In 1748, after many disputes about monetary policy, President Harry S Truman replaced Mr. Eccles as chairman of the Federal Reserve System board of governors. It was though at the time that Mr. Eccles would leave government, but he remained a member of the board for another three years.

By the time he did leave, an agreement had been reached under which the Federal Reserve System governors won control from the Treasury over decisions involving money and credit.

William McChesney Martin had been named chairman of the Federal reserve System and Mr. Eccles felt that the system was in good hands, according to a collegue. Since that time, he had tended to his business interests.

Survivors include his wife, Sara, a daughter, a son, two brothers and four sisters.