Aberdeen Proving Grounds in eastern Maryland is receiving more military construction money than any other Army facility in the country, and Rep. Roy Dyson (D-Md.) is coming back for more.

In what has become an annual spring ritual, Dyson has joined dozens of members of Congress, some opponents of increased defense spending, who are grappling for more construction money for military bases back home.

Dyson persuaded Congress last year to add several major construction projects to the base in his district, which is receiving $96 million this year. He is also one of a dozen lawmakers who have signed up to testify for new projects later this month before the House Armed Services subcommittee on military installations and facilities.

"I just personally lobbied the committee members long and hard, and we got what we needed," Dyson said, referring to Aberdeen's new family housing, chapel, day-care center and other projects. "I'm going to look out for home; I was sent here to do that."

It is one of the ironies of congressional life that the supplicants include a number of Democratic liberals seeking millions of dollars for home-state projects while arguing that the defense budget should be cut.

Rep. Barbara Boxer (D-Calif.), for example, supports a freeze on defense spending. But she is seeking extra funding for two Navy projects in her San Francisco district. She said she is asking for less than she would like.

"I would agree that in years past I came in with a wish list, but not any more," Boxer said. "This is real bread-and-butter stuff. I told my shipyard people that I cannot have a potpourri of things that you need, because this isn't the year."

The military installations subcommittee deals with a side of the defense budget that receives far less attention than the MX missile or Trident submarine, but is no less dear to the hearts of members of Congress. Every spring, dozens of House members descend on the panel with requests for "add-ons," ranging from troop barracks to sewer connections.

The lobbying will be especially intense this year. Subcommittee Chairman Ronald V. Dellums (D-Calif.) has served notice that he plans to cut President Reagan's proposed $10 billion military construction budget by $1 billion, as he did last year. Senators will be making similar requests to a subcommittee headed by Strom Thurmond (R-S.C.).

Boxer is seeking $4 million to help replace an outmoded sewer system at California's Mare Island Naval Shipyard, which she says is dumping raw sewage into San Francisco Bay. She also is lobbying for design money for a $40 million engineering and planning building for Mare Island employes who now work out of trailers.

Boxer argued that administration officials "have spent their funds on overkill nuclear weapons and procurement. They are really abandoning their obligation to the average person in the military, who is asked to work in substandard conditions. We don't need weapons systems like the MX; we've got to take care of our people on the ground."

Many advocates contend that Congress routinely votes money for costly new weapons while neglecting the decaying, World War II facilities in which most of the construction and repair work is done.

"When you start cutting the defense budget, the first place they cut is military construction, the stuff that takes care of the bases," said Sandra Stuart, an aide to Rep. Vic Fazio (D-Calif.). "They're the less sexy accounts."

Fazio, who favors a cut in defense spending, is supporting $53 million in proposed spending at McClellan Air Force Base in his Sacramento district. Stuart said Fazio has limited his suggested add-ons to $5.8 million for sewer facilities there, but agreed that some members show little restraint.

"Everyone is screaming about the enormous defense budget," Stuart said. "How can you on the one hand scream about these big weapons systems, and on the other hand yell for more buildings back home where they fix the weapons systems?"

The list goes on. Rep. William V. (Bill) Alexander Jr. (D-Ark.) is pushing for $1.5 million to renovate a chapel and add a religious education center at Blytheville Air Force Base in Arkansas, along with a $510,000 petroleum facility and $480,000 family support center.

Another subcommittee member, G.V. (Sonny) Montgomery (D-Miss.), has signed up to testify for an additional $100 million to improve facilities for the National Guard and armed forces reserves, which asked him to make the requests.

"You have to speak up for the things you think you need," Montgomery said. "These are low-cost items that I'm talking about. I'm not trying to add to the budget deficit."

Dyson, a former member of the installations subcommittee, knows how to cultivate support for his projects. He has taken Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) and other House leaders on the 45-minute flight to Aberdeen to watch the M1 tank and other weapons be tested, then made sure they toured the dilapidated housing that he was seeking to replace.

This year Dyson is lobbying for $3.2 million for a ballistics research laboratory for aircraft testing, which now is done outside on the Aberdeen grounds.

Asked whether such requests amount to pork barrel projects, Dyson said, "You certainly could say that. But for a decade, the Army thought about closing Aberdeen and there was virtually no construction there. We got the short end of the stick. We're just trying to play catchup."

Other members are trying to protect items that are already in Reagan's 1986 budget request from being deleted to fund someone else's project.

Rep. Leon E. Panetta (D-Calif.) is supporting $117 million for his district, most for housing, a supply warehouse and other facilities at California's Fort Ord. Rep. Norman D. Dicks (D-Wash.) is supporting funding for a $338 million expansion of an aging Army hospital in Tacoma.

Rep. Lindsay Thomas (D-Ga.) is assured of $400 million in construction at Kings Bay, Ga., one of the two Trident submarine bases. But he is particularly determined to keep $6.1 million in "community impact assistance" to help surrounding towns cope with the new base.