The Army will deliberately stunt its troop growth over the next several years to free money for its biggest weapons-buying spree since World War II.

The decision to favor weapons over people is the biggest force shaping the Army's new five-year plan, now under review at the Pentagon, with fiscal 1984 the starting point.

The basic problem is that the Army has so many big bills coming due for major new weapons systems. It has ordered more weapons than it can pay for unless it holds down people costs.

Gen. Edward C. (Shy) Meyer, Army chief of staff, so far has beat down challenges to his slow-growth troop policy during secret sessions of the Defense Resources Board on the fiscal 1984 through 1988 blueprint, officials said yesterday. His opponents contended that the recession has presented the Army with a golden opportunity to expand because more men and women are trying to enlist than can be accepted under current personnel ceilings.

If Meyer continues to prevail over those who want to "stockpile" volunteers, the Army, though it is the military branch which needs the most people, will grow slower than other services over the next six years. Its growth rate is projected to be half that of the Navy and Air Force, and even less than the Marine Corps, one-quarter the Army's size.

Defense Secretary Caspar W. Weinberger, in going along with Meyer, is signaling a shift in administration thinking on what needs to be done first to rearm America under President Reagan's blueprint. This time last year Weinberger in his secret policy guidance to the Army called for a "major expansion of force structure," meaning additional divisions.

The Army may have chilled Weinberger and other fast-growth advocates by warning in a secret memo last summer that it would take almost 100,000 more soldiers above those then in uniform to build the extra units required to carry out Weinberger's policy guidance. The Army should grow to 870,000 by 1987 to do the job the administration had cut out for it, the memo said.

It added that there was little hope of recruiting enough volunteers to reach 870,000 by 1987, making the draft the only sure solution.

The projected size of the Army has since been lowered to 819,000 for 1987, a growth of only 35,000 people over its authorized strength of 784,000 for this fiscal year. This modest 4.5 percent increase compares with growth rates of 9 percent for the Navy and 10.5 percent for the Air Force, which are planning to go up by 50,000 and 59,000 people, respectively, in the same period.

"Our immediate objective with regard to force structure and modernization is to modernize the existing 24-division force 16 active and eight National Guard in reserve status before attempting to increase the number of divisions," said Meyer and Army Secretary John O. Marsh Jr. in making their case to Congress.

They said this approach would accomplish "the two most critical tasks facing the Army today: first, equipping the force to improve readiness, and second, providing a sufficient level of modernization to assure deterrence." In case the Army should have to fight the Soviets, the Army leaders added, buying modern weapons at the expense of extra divisions would help assure that American troops would be able to offset the Soviet edge in manpower, tanks and cannon.

"I'm on Shy's side," said a top Pentagon executive from the Carter administration in applauding the slow-growth decision. "If we need more divisions, let the Europeans provide them, especially since we don't have the air and sea lift needed to get them to Europe anyway."

Gen. Maxwell R. Thurman said in an interview yesterday that as the Army's manpower chief he would like to get more volunteers while the getting is good. But he said he understands the rationale of the "significant policy decision" to settle for slow growth in manpower.

"It does two things," Thurman said. "It modernizes the active component and also modernizes National Guard and reserves." Delivering the new M1 tanks to active duty units makes the older but still prized M60 tanks available to the reserves, he said in giving one example of the double dividend.

"The decision is to stabilize end strength and buy hardware," since there will not be enough money to put thousands of new soldiers on the payroll and buy all the new weapons now going into production as well, he said.

"Those Army leaders are kidding themselves when they say holding down on manpower will give them the money they need for weapons," said one Pentagon official who has sifted through the Army's five-year plan. He said the Army has bitten off more than it can chew in ordering so many weapons at once.

Another Pentagon official said that besides the Army's "bow wave problem" of having too many bills for weapons coming due at once, the Army is losing out to the Air Force's strategic purchases, notably the B1 bomber and MX missile when it comes to dividing up the Pentagon's money pie this year.

The General Accounting Office has lent credence to the contention that the Army has ordered far more weapons that it will be able to pay for, even after holding down troop growth.

Noting that the Army is trying to put at least 14 major weapons in the field at once, including the M1 tank, AH64 attack helicopter, Pershing II missile and the Division Air Defense Gun, GAO said "not only is there some concern regarding the availability of sufficient procurement funds to buy the weapons at economical rates, but there is also growing concern about the accompanying operation and support costs that will be required over the next 10 to 20 years."

"Something has to go," said one Pentagon official who has reviewed the Army's shopping list. The Division Air Defense Gun is one of the big weapons that has been on and off the chopping block at recent Defense Resources Board meetings on the fiscal 1984 budget, along with less glamorous items like new trucks.

But there is no sign that the Army intends to change its main budget objective of getting new weapons before it gets new people.

This is the first in a planned occasional series of articles on budget problems of the individual military services.