A sharply rising weapons procurement program to buy 26 warships, 697 military aircraft, 3,000 tanks and other armored vehicles and 45,000 missiles is the most striking feature of President Ford's new Defense Department budget proposal.

If Ford's plan is followed, the government will be authorized to spend $35 billion for weapons purchases - 25 per cent more than in the current fiscal year. The proposed new weapons cost is more than three times what the federal government plans to spend on welfare payments or environment programs during fiscal 1978.

Among the weapons being purchased is the Trident nuclear submarine, which will be able to launch 192 nuclear warheads at different targets from an undersea platform almost as along as two football fields and a high as a four-story office building. It has been called the most expensive weapons system ever built. The new Pentagon budget includes $1.7 million to buy two of the giant submarines plus $1.1 billion for missiles to arm them. The first Test launch of a Trident missile is scheduled for today at Cape Canaveral, Fla.

Another major recommendation is purchase of the controversial B-1 bomber, which Congress refused to order into production late last year and which President-elect Jimmy Carter referred to in his campaign as "wasteful of taxpayers' dollars."

Ford recommended $1.7 billion in procurement money for the B-1 in the new budget. The Air Force hopes to buy 244 of the four-engine supersonic bombers at a cost of $22.9 billion or $94 million per plane. Secretary of Defense-designate Harold Brown recently told Congress that he will study the need for the B-1 and hinted that he is sympathetic.

The Navy is in the midst of a ship construction program to rebuild the fleet to 600 ships. In a potentially controversial proposal, Ford decided against building additional large-deck, nuclear-propelled aircraft carriers backed by Adm. Hyman G. Rickover and some members of Congress The President instead proposed designing smaller and less expensive carriers run on conventional fuel.

A briefing book provided by the Pentagon lists 106 weapons systems to be purchased in its new budget, including 18 types of Navy aircraft, eight types of Air Force aircraft and 22 missile systems for the services. An additional 31 weapons systems of the future are listed for "research and development."

An important feature of the proposed "research and development" budget of $12 billion - which is $1.5 billion more than this year - if "full-scale development" of a giant, new multiple-warhead MX intercontinental ballistic missile, estimated to be three times as powerful as Minuteman III missiles in underground silos. Ford recommended $294 million for development of the MX this year, but Pentagon specialists have estimated an ultimate cost of $30 billion for the program.

Ford also proposed full development of a new family of cruise missiles essentially pilotless bombers that could be fired deep into the Soviet Union from submarine, airplane or land launchers. The cruise missile is a matter of dispute in Strategic Arms Limitation Talks (SALT) with the Soviet Union and is considered a complicating factor in any future arms control arragements.

Military outlays in the new budget are $112.3 billion, but the military is asking for permission to make commitments to spend $123 billion, the figures the Pentagon uses in most of its computations. The justification for the sharp increase in defense procurement and other military costs is the steady Soviet military growth over the past decade. A Pentagon statement said Soviet defense spending is estimated to be"at least 35 per cent greater than that of the U.S. today."

In a briefing for reporters, Secretary of Defense Donald H. Rumsfeld said the U.S. military increase is necessary to make up for declining efforts, measured in non-inflated dollars and excluding Vietnam spending, over the past 15 years. Ford's fiscal 1976 budget increased military spending on operating programs by 2 per cent (adjusted for inflation), and the fiscal 1977 military budget is up an additional 5.8 per cent, Rumsfeld said. The new budget proposal represents an additional increase of 6.7 per cent, he calculated.

Despite its size, Rumsfeld called the new budget proposal "sound and austere." He added that "no attempt was made to please those individuals who have it as their task every morning when they get up to find a way to hack the defense budget."

Rumsfeld expressed doubt that Carter will be able to fulfill his campaign promise of cutting $5 billion to $7 billion from defense costs by redeployment and better management without degrading U.S. defenses. "If anyone suggests that suddenly this building [the Pentagon] is going to turn into a model of perfect efficiency - no waste - they're dreaming Rumsfeld said.

He maintained, however, that Pentagon efficiency is higher than that of other U.S. departments and said that its record for cost over-runs is better than the Washington Metro system, the San Francisco Bay Area transit system or the John Hancock building in Boston. He did not give figures to back up this claim.

The United States has about 9,000 strategic nuclear weapons capable of being launched against the Soviet Union, compared with an estimated 3,500 Soviet strategic nuclear weapons that are a potential threat to the United states.The new U.S. budget proposes $2.3 billion in military-related nuclear programs, largely production and testing of atomic warheads, in additional to Department of Defense spending.

Breakdowns of the military budget given to reporters indicate that "general purpose forces" rather than "strategic forces" account for the greatest share of budget increases. The Army is continuing a re-equipment program in a buildup from 13 to 16 divisions, and the Air Force is buying warplanes to complete a buildup from 22 fully equipped air wings to 26, military specialists said.

Ford's budget message said the conventional forces are being equipped "to fight a high-intensity war and to respond rapidly in the case of a European conflict." New tanks, artillery, helicopters, antitank and antiaircraft missiles for the Army are designed to add to its ability to fight tank-heavy Soviet forces in Europe.

The proposed budget calls for U.S. armed forces to remain stable at 2,090,000 men and women. The Defense Department's civilian payroll is listed at 1,031,000 workers.

An additional 217,000 workers in defense-related industries would be hired under the budget proposals to make the new weapons planned, bringing the military industry work-force to more than 2,000,000.

About 5,180,000 Americans would derive their paychecks, military and civilian, from the proposed new military budget.