MOSCOW, SEPT. 3 -- Russian President Boris Yeltsin opened his republic's legislature today with a ringing call for abandonment of the "dictatorial" Soviet economic system in favor of a radical program to stabilize the economy and allow widespread privatization and introduction of market forces.

Yeltsin's so-called "500-Day Plan," detailed in a 600-page document handed out to Russian legislators today, proposes deregulation of prices on nearly all goods except essential foodstuffs, a 75 percent cut in Soviet foreign aid, creation of a commercial banking system and stock and currency markets, liquidation of numerous planning ministries and legalization of private property.

Although government sources said that Soviet President Mikhail Gorbachev is likely to approve the 500-Day program on a national level this month, the Soviet leader has indicated he also may seek to include in it some of the more conservative reform methods proposed by Soviet Premier Nikolai Ryzhkov. Yeltsin's aides say Gorbachev has endorsed the radical program "in principle, but not yet in final political fact."

Yeltsin said today that Ryzhkov should resign and that the Russian legislature would consider only the more radical program. "We need a transition from an ideology-driven economy to an efficiency-driven economy," he said in his opening speech. "There are hardly any wealthy areas left in the country. Poverty, and even misery, are widespread, and living standards continue to plunge."

Yeltsin's political strategy seems to be to make it clear to Gorbachev that there will be no compromise on radical economic reform in Russia, a republic of 147 million people that contains the bulk of the Soviet Union's land and resources. By approving the reform package without waiting for Gorbachev's national government to act, the Russian legislature would effectively set the agenda for economic change in the Soviet Union -- an agenda that would grant broad economic controls to the country's 15 constituent republics and limit Moscow's power.

As one of Yeltsin's close aides put it: "Even if Gorbachev wanted to use some of Ryzhkov's plans, he couldn't. Russia makes that impossible."

The 500-Day Plan was drafted by a team of Yeltsin's advisers and with the eventual collaboration of one of Gorbachev's closest economic aides, Stanislav Shatalin. Also known as the Shatalin Program, its backers hope to see it put into effect Oct. 1. Its principal goal is the "economic freedom of all citizens" and creation of a "new model" of Soviet society, "the basis of which is the entrepeneur and the enterprise multiplying their property."

The plan calls for reforms to be implemented in phases, according to a strict timetable. The first 100 days, beginning Oct. 1, would involve a "program of extraordinary measures" instituted by leaders of the 15 Soviet republics, including the massive sale of state properties, unfinished construction projects and military properties used for civil purposes. The plan also calls for land reforms that would allow farmers to withdraw from collective farms and receive "their share of the land."

The plan also envisions reduction of the national budget deficit, in part through a 75 percent cut in foreign aid and cuts of 10 percent for the military and 20 percent for the KGB.

During the initial period, the Soviet Union would also try to sell on world markets debts owed to it by other countries. The state banking apparatus would be reorganized into a reserve system comprising the central banks of all Soviet republics. Other financial institutions would be developed into joint-stock banks and commercial banks.

On Nov. 1, the Soviet Union would begin a currency-reform program intended to lead to the stabilization and the eventual convertibility of the ruble on world markets. By early 1991 there would be gradual state-enforced price reform, although prices of staple foods would be frozen.

Days 100 to 250 would see a further liberalization of prices. "The authors assume," says the outline, "that after the first stage the consumer market will have improved, especially regarding goods sold on a supply-and-demand basis," such as appliances. At the same time, interest rates for bank loans would increase, as would the number of state-run enterprises converted to joint-stock enterprises.

The state would sell bonds and enterprises to decrease the budget deficit further and would expand opportunities for individuals to buy, on credit, the property and means to open small businesses, shops and restaurants. In this period, the plan calls for half of all small shops and restaurants to be privatized.

Most economists here believe the transfer to a market economy, which would involve the closing of unprofitable state-run enterprises, would accelerate unemployment. Vladimir Shcherbakov, the chairman of the Soviet State Committee for Labor and Social Affairs, said that 10 million to 12 million workers will "face redundancy in the months ahead."

Toward the end of the 250-to-400-day period, the plan foresees the "stabilization of the market." Up to 40 percent of fixed assets in industry, 50 percent of those in construction and automotive transport and 60 percent of those in trade and services would be removed from state control.

To help create a convertible ruble -- considered essential for Soviet entry into the integrated world economy -- the plan calls for the creation of currency and stock markets and a commercial banking system.

Days 400 to 500, the plan says, should mark "the start of the revival. . . . The authors assume that by this time all prerequisites for a tangible strengthening of economic activity should be in place, above all in light industry and food industries, agriculture and the service sector," the plan reads. It says that during this period there should be a reasonably stable price system and state budget, a modern banking system and a currency market. The program also calls in this period for privatization of 70 percent of all industrial enterprises and of 90 percent of the construction and retail trades.