Montgomery County's 26-member legislative delegation arrives in the capital today with more than a few fears about the opening of the 90-day session of the Maryland General Assembly.

With a stark state budget threatening programs in every jurisdiction, Montgomery's legislators say their greatest energies in 1983 will be spent keeping the county's financial losses to a minimum.

"This year, with money being short, we're hoping we can hold on to what we've got," said Democratic Del. Ida G. Ruben, head of the county's 19-member House delegation. "We all have needs. We want to arrive at an equitable solution for everybody."

Montgomery's legislators have struggled for years to win political clout in the statehouse and to challenge a once commonly held view that the county was too wealthy to deserve state funding for cherished programs such as Metro and public education.

This year those sorts of battles may be even tougher.

"There are a lot of financial problems this session and not a lot of money," said Democratic state Sen. Laurence Levitan, chairman of the Senate Budget and Taxation Committee. "And there are some areas we could end up losing."

Most worrisome to Montgomery legislators is the threat of reduced state funds for Metro and for coveted transportation projects, such as road construction along the I-270 corridor.

Just last week, Montgomery legislators were worried that state officials were planning new funding formulas for transportation programs--formulas that could shrink Montgomery's ratio of state money--as a way to offset the state's projected $125-million deficit.

Specifically, Gov. Harry Hughes had suggested a possible transfer of corporate tax revenues, now earmarked for the state's transportation trust fund, into the state's larger pool of "general" funds.

(The state allocates money from general funds to pay for programs that do not involve transportation or construction. Maryland law requires a balanced state budget, so Hughes must find a way to bolster the general funds account and erase the deficit, whether by cutting programs, raising taxes or transferring money from other sources, such as the transportation trust fund.)

Simmering on the back burner for Montgomery is an equally complicated and nettlesome dispute over state formulas for local school funding, formulas that may not be clarified until next year.

At issue is whether local jurisdictions, all of which receive some state aid for education, can be forced to impose a ceiling on their own levels of per-pupil spending.

Montgomery currently spends more than any other jurisdiction in the state on its students, a practice that was struck down in court last year as being unfair to students in poorer jurisdictions. The case awaits review by the Maryland Court of Appeals.

Complicating the whole legislative picture for Montgomery is the precarious fiscal situation in neighboring Prince George's County. A voter-mandated property tax freeze there, known as TRIM, has squeezed the county's finances so much that some legislators from other jurisdictions are worried that Prince George's will look to Annapolis for an economic bail-out.

"A lot of this session for Montgomery is going to depend on what other counties do," said Democratic Del. Nancy K. Kopp, a vice chairwoman of the powerful House Appropriations Committee. "Prince George's may try to move people through various means."

Levitan said: "I don't think the state should come in and lift them out. What the voters want, they ought to get."

Irksome to some legislators is a possible move by the Prince George's delegation to ask the General Assembly to approve a local sales tax to bolster the county's sagging revenues. That idea does not sit well with Montgomery's representatives.

The fears in Montgomery are that Prince George's efforts to get state funding or approval for new forms of taxation--after their voters rejected a property tax increase--could jeopardize regional projects, such as Metro, that are funded partly with money from the state coffers.

"We don't want to give the state any reason to back away from funding Metro ," said Montgomery Republican state Sen. Howard A. Denis. "What we want now is the status quo. We shouldn't do anything to threaten the apple cart."

This year, like almost every year in recent memory, the Montgomery delegation probably will go through its usual motions for key local bills. The perennial hot potatoes--new tax assessments for country clubs and developed farm land--are almost certain to be discussed, but they don't seem to arouse the passions they once did.

In 1983, it seems, the mood is mainly one of hunkering down and stressing the need for statewide "unity."

"There is so much uncertainty about the revenue picture that we're just waiting for the other shoe to fall," said Democratic. Del. Lucille Maurer, chairman of a newly established joint committee on federal-state relations. "In all places, it's a question of just hanging on."

Del. Donald B. Robertson, the House majority leader, said: "It's not going to be a year of creating new programs and reallocating new formulas for jurisdictions. Next year will be."