In a determined effort to convince Europeans and Americans of the Soviet military threat, the Pentagon released a 99-page declassified report yesterday on "Soviet Military Power" that paints an awesome portrait of the U.S.S.R. as a military machine with an insatiable appetite for planes, tanks, submarines and missiles.

The report--a glossy, picture-filled production printed by the Government Printing Office--was introduced by Defense Secretary Caspar W. Weinberger at a crowded Pentagon news conference that was televised live via satellite to Europe courtesy of the State Department's International Communication Agency.

The report contains some new detail but no startling disclosures beyond information previously made available in congressional testimony and in annual U.S. military "posture statements" by previous defense secretaries to Congress.

Unlike those posture statements, however, there is no overall comparison in the new Soviet threat report with potentially offsetting Western military strengths. Those comparisons that are included are primarily longstanding and well-known unfavorable balances in tank, submarine and antiaircraft missile inventories and production. Thus, while neither Weinberger nor the report goes so far as to proclaim that Moscow has overall military superiority over the West, that is the impression left by the document.

Weinberger said the report is not "scare tactics" or "any kind of propaganda" and that there is "nothing at all hypothetical about the Soviet military threat." The report, he said, "is a factual document" that "contains more information on the the U.S.S.R. armed forces than has ever before been available under one cover in an unclassified presentation."

Similarly, he said the timing of the release of the report was "purely coincidental" when asked if it had anything to do with the forthcoming announcements by President Reagan on the MX missile and B1 bomber programs.

Weinberger asserted that the work on the unclassified version of the report began after allied leaders who had heard the secret version aired in North Atlantic Treaty Organization meetings earlier in the year asked if it could be declassifed so the public at large could be exposed to the data.

It has been known for months that the Pentagon was working on such a report and administration officials have said privately that it was meant to be part of a public relations campaign aimed especially at NATO allies in Western Europe.

There has been growing public opposition in some countries, especially West Germany, to the planned deployment of new U.S. Pershing II and cruise missiles in NATO countries to offset Soviet SS20 missiles already in place, and to the announcement that the Reagan administration would also begin assembling neutron weapons in this country for possible use in Europe.

Key points in the report and those made by Weinberger include:

The Soviets now have 4.8 million men under arms, including more than 180 army divisions at various stages of readiness, an increase of 30 divisions since 1967. Thirty divisions, the ones most combat ready, are in Eastern Europe while 80 more are in the western U.S.S.R. and some 70 are positioned near the Chinese and other Asian borders.

The Soviets have fielded 50,000 tanks and 20,000 artillery pieces, and their current advantage of more than three to one over the West in Europe in these categories is expected to grow even larger.

In each of the last eight years, the Soviets have produced more than 1,000 fighter planes, about double the U.S. rate. More than 3,500 Soviet and Warsaw Pact fighters and fighter-bombers are now based in Eastern Europe alone, outside of the Soviet Union, and the total Soviet helicopter fleet now numbers more than 5,200 craft.

The Soviets already have fielded 250 of the new triple-warhead, intermediate-range SS20 missiles, with another 65 launchers known to be under construction. The report estimated that as many as 100 or 150 additional SS20 launchers may be built and says that each launcher has an extra missile for refire capability.

Moscow now has some 150 new Backfire intermediate-range bombers deployed and is building more at the rate of about 30 per year.

Eight different classes of submarines and eight classes of major surface warships are presently under construction. The Soviets have five major shipyards that are building submarines.

There are more than 135 major military industrial plants now operating with 40 million square meters of floor space, an increase of 34 percent over 1970. To underscore the size of the Soviet industrial base, the report contains an outline of the Soviet railroad car and tank plant at Nizhniy Tagil that shows it would cover the two miles between the Capitol and the Washington Monument if it were relocated here. The plant, according to the report produced by the U.S. intelligence community, turned out 2,500 new T72 tanks in 1980 alone.

The Soviets have 20 surface ships, 70 submarines and 300 aircraft already armed with antiship cruise missiles, have a substantial lead in chemical warfare, have 180 nuclear-powered submarines in comparison to 115 in the U.S. fleet and have 115,000 people working full-time in a $2 billion annual civil defense effort.

While the United States still leads the Soviet Union by two to seven years in microelectronic, computer and jet engine technology, the West's technological lead is rapidly eroding in electro-optical sensors, guidance and navigation, hydro-acoustics, optics and propulsion.

The Soviets devote an average 12 to 14 percent of their gross national product to defense and the estimated dollar-cost of Moscow's military investment was 70 percent higher than comparable U.S. spending in 1979.

The report also includes the first depiction, in the form of artist sketches presumably made from satellite pictures, of the new SS20 missile and Typhoon missile-firing submarine as well as maps showing in general the regions where Soviet missiles are deployed.

It is widely accepted among specialists that the Soviets have indeed built up a big and powerful military force. But what is missing from the new report are several offsetting factors.

For example, while NATO is outgunned on tanks, the West has added tens of thousands of antitank missiles to its force in recent years and the Soviets have nothing to match the fleet of 13 big U.S. aircraft carriers. Allied spending, when the United States and Western Europe are taken together, still is greater than Soviet and Warsaw Pact spending.

The United States has more reliable and more militarily potent allies than does Moscow. The report shows 53 non-Soviet Warsaw Pact divisions in Eastern Europe. But 15 of those are Polish, and they probably trouble Moscow more than they do Washington.

The Soviet navy faces potentially disastrous geographical bottlenecks in getting into the open ocean from the Baltic and Black seas and the far North Atlantic in a crisis. There is no assessment of morale, drinking and ethnic problems within the Soviet armed forces, nor of the rather lengthy mobilization times required. Much of the army increase is because China has become an enemy rather than friend.

In his last defense posture report to Congress in January, 1981, then-defense secretary Harold Brown cautioned against "simplistic static indicators" as a true measure of the military balance. While also cautioning against adverse trends, Brown pointed out that allied military manpower is greater than commonly realized and that aircraft-for-aircraft, NATO still maintains a performance edge in fighter aircraft over the Warsaw Pact.