Defense Secretary Caspar W. Weinberger, in his annual report sent to Congress today, accuses the Soviet Union of violating treaties on biological weaponry and calls, in the strongest terms, for restrictions on western trade, technology and credit that "help preserve the Soviet Union as a totalitarian dictatorship."

The 324-page report, which describes an evolving military strategy of countering the Soviets where they are vulnerable rather than only where they may attack in strength, also establishes the gentlemanly and soft-spoken Weinberger as probably the most hard-line, anti-Soviet voice to emerge publicly in an American Cabinet in many years.

The report is meant to outline and support a record $1.6 trillion, five-year defense plan to build up forces that the president and Weinberger contend had been allowed to deteriorate badly in the last decade, especially during the Carter administration, while a Soviet buildup proceeded without interruption.

Although it is normal for a defense secretary to invoke the Soviet threat to support higher budgets, the sweep of Weinberger's denunciations go beyond traditional military concerns and into the field of trade. They come when the administration is divided over how to manage its fundamental economic relationship with Moscow.

Although the Pentagon was alone last week in opposing an administration decision to pay off U.S. banks that were owed money by Poland rather than allowing Poland to go into default, Weinberger is a close and influential adviser to President Reagan and his report makes clear the battle is far from over.

In the report, issued while Weinberger is traveling in the Mideast, he says, "I have the responsibility to tell you that, in my view, no defense policy, no strategy could succeed in the long run unless we pursue a policy that ensures that our resources will not be diverted to strengthen our adversary.

"The only domain in which Soviet communism has not proved to be a failure is the practice of military imperialism," he says.

American defense strategy must do two things: halt further expansion of the Soviet empire and see to it that western productivity and technology "are not exploited to make good the chronic deficiencies of the communist system."

"If the economy of the Soviet empire is propped up by western credits," Weinberger says, the Soviets can divert other funds to build weapons with which to threaten the West. Purchase of Soviet raw materials such as natural gas, which West Europeans are about to do on a massive scale, sends western money to buy arms with.

Western technology keeps Soviet industry from becoming obsolescent and thus allows the Kremlin, with its "fatally flawed" central planning system, to avoid choosing between its military priorities and modernization, he claims.

It is "a testimony to the degree of our past blindness," Weinberger contends, that so much western trade has flowed eastward that Moscow now has leverage on the West rather than the other way around.

In another broadside, as the United States also ponders what to do about continuing talks with Moscow on controlling nuclear missiles, Weinberger says America "now has many good reasons for believing that the Soviet Union has violated the Biological Weapons Convention" of 1925.

Weinberger cites a 1979 accident in the Soviet city of Sverdlovsk that suggested biological weapons may be produced there secretly and more recent "evidence" of toxic weapons' being used in Laos, Cambodia and Afghanistan.

Although these incidents have been known for some time, Weinberger says these alleged violations "create a most serious problem for any new arms agreement with the Soviet Union." What is left, he asks, of the concept of verifiability if the Soviets are cheating?

In putting forward a record peacetime defense increase in combination with a warning that "there is nothing hypothetical about Soviet military power . . . it is the single greatest threat to the United States and the free world," Weinberger is trying to do some things other than just get the budget through Congress and send a signal to Moscow, officials say.

One may be, as some suggest, to prepare U.S. public opinion for a prolonged period of U.S.-Soviet tensions. Weinberger is also aware that big defense hikes in the face of domestic cutbacks risk breaking the fragile public consensus for a military buildup.

But he believes the threat is real and that it is necessary to run that risk in order to get as much of the buildup paid for while support lasts.

The strong anti-Soviet tone of Weinberger's report contrasts with his description of American military forces as suffering from "a decade of neglect" and will undoubtedly raise questions about challenging the Soviets if U.S. forces are not strong enough.

But a key part of the strategy laid out by Weinberger is that the nation "might choose not to restrict ourselves to meeting aggression on its own immediate front." Rather, he says, the United States might counterattack in places where the enemy is more vulnerable.

Suggesting that the Soviets have vulnerabilities in their own empire, he specifically alludes to the turmoil in Eastern Europe, and may also have had Soviet Asia in mind.

Weinberger also calls attention to Soviet-supplied military strength in Cuba that could hamper allied shipping in a European conflict, which could suggest a possible U.S. counter there. He also notes possible Soviet efforts to extend its reach into Iran.

Rather than the traditional focus on European defense, Weinberger stresses the need for the United States to get at least some forces fast to any global trouble spot, especially the Persian Gulf, and be able to fight there.

Actually, the ideas of rapidly deployable forces and striking back at points other than the enemy's strength were part of an evolving Carter administration strategy. They are being pursued vigorously in an attempt by the Reagan administration to tie the defense program more tightly to the rhetoric.

This is reflected in huge budgetary increases to expand airlift and sealift forces, to expand the Navy to fight anywhere, and in a variety of quick fixes, such as bringing old battleships out of mothballs and deploying thousands of new cruise missiles at sea.

The five-year defense plan suggests it will be mostly the Navy and Air Force that carry out this new wide-ranging strategy, with a planned expansion eventually of two more air wings each for the Air Force, Navy and Air National Guard, plus a buildup from a 450- to a 600-ship Navy.

For reinforcing Europe, Weinberger says the United States wants to be able to move six Army divisions, a Marine brigade, 60 fighter squadrons and their support to Europe within 10 days, a time frame that is nowhere near attainable today.

In essense, Weinberger says America "cannot settle in advance" how, where or how long it may have to fight. So previous assumptions about having enough forces to fight "one-and-a-half wars" or other "fallacies," such as the notion that future wars will be short, must be discarded.

In addition, he says the alliance must also change the way it reacts to warning signs. Recalling how many times in history when warning signs were overlooked and failed to trigger a response in time, he argues that the ability to respond to "ambiguous warning" must be improved.

Weinberger also says taxpayers in allied countries must take on a fairer share of the burden, and he calls on an especially prosperous Japan to beef-up its defenses in waters out to 1,000 miles away.