Harry R. Hughes, elected governor of Maryland on Tuesday with the state's greatest landslide in this century, said yesterday his mandate was to move slowly.

"I suppose we'll ease in little bit in the first year," he explained. "As I said in the campaign, government is not simple."

Eight years ago, when he was elected to the same job, Marvin Mandel promised the opposite. "I shall govern," he proclaimed, and then passed hundreds of laws and expanded the government at a rate surpassing any other state in the Union.

Mandel also became the state's first sitting governor to be convicted on political corruption charges, and one who went through a public and painful divorce.

In this first post-Mandel election, voters have chosen an understated politician from the Eastern Shore who never came close to scandal in 25 years in state government.

"Harry has charisma in a quiet, Will Rogers kind of way," said Del. John Hanson Briscoe, outgoing speaker of Maryland's House of Delegates. "He makes you feel comfortable. He exemplies the opposite of the backslapping political crony."

Annapolis under Mandel was like a Southern county seat. Mandel watched over every bill, appointment and budget appropriation to such an extent that legislators felt they could do little without the approval of "the Man on the second floor," where Mandel ruled from his executive suite.

Through his patronage, his obsesively secret style and his adept vote trading, Mandel controlled not only Annapolis but the towns and counties dependent on state government for bridges, highways and education money.

As chief executive, Mandel steered state government through its most expansive period. He reorganized government, enacted a strict gun control law bought the old Friendship Airport, passed restrictive air pollution and water pollution controls and set up agencies to regulate hospital costs, obtain power plant sites and insure drivers rejected by private insurers.

The aggressive role of government under Mandel had its costs, creating problems that became central issues of this year's campaign. While the state bureaucracy doubled and the budget quadrupled, Maryland lost 41,000 manufacturing jobs and the state's tax burden became the fifth highest in the nation.

"People want government to back off," said Del. Gerald F. Delvin (D-Prince George's). "Even liberals say they just want government to leave them alone. Harry made the right noises in that way."

Hughes, who served as Mandel's transportation secretary and helped enact many of the state's liberal spending programs as state Senate majority leader in the 1960s, was one of the first candidates to question the liberal Democratic philosophy that government can solve all our problems.

From the beginning of his 14-month election drive, Hughes promised only to do "what I can do." Instead of the grand designer, he portrayed himself as a tinker, a governor who would consolidate past gains, streamline government spending programs and decentralize the executive power accumulated by Mandel.

Hughes resigned in protest from Mandel's cabinet last year after accusing a politically influential contractor of "tampering" with the award of a subway contract. He often grimaced during the campaign when talking about Mandel's domination of department chiefs.

"People should have the power that goes with their jobs," he said on the campaign trail, promising to give greater authority to his cabinet secretaries. "They should be accountable for what they do. That didn't happen before."

At his press conference yesterday, Hughes said he has set up an 18-member transition team charged with preparing briefing books on the problems of all state agencied, commissions and departments. The team also is expected to solicit prospects for cabinet positions from groups like the legislature's Black Caucus and the League of Women Voters.

Of his cabinet secretaries, he would only say, "There will be at least one black and at least one woman in my cabinet and it will not be a black were using a drug that works on the woman."

The General Assembly is included in Hughes' plan to allow all officials greater independence. "I do not intend to dictate or influence either the House or the Senate. They can choose their own leaders. I prefer to have both houses organize themselves."

What Hughes has vowed to keep his hands off is a total change that will occur in the legislature's leadership. State Senate President Steny H. Hoyer abdicated his position when he ran unsuccessfully for lieutenant governor. The Senate majority leader, Roy N. Staten, has retired.

So has Briscoe, who did not seek reelection and has vacated his position as speaker of the House of Delegates. House majority leader Del. John S. Arnick, lost his bid for State Senate.

The four most powerful state legislative positions are open, an unusual situation from which Mandel could never have kept away.

The voters also gave the legislature more independence from the governor by approving a constitutional amendment, Question 6, which requires the governor to fund all programs passed by the legislature. The question arose after Mandel refused to finance a foster care program.

"Harry Hughes is going to let people do their own thing and make sure they're doing the right thing," predicted Del. Benjamin L. Cardin (D-Baltimore), a likely candidate for speaker of the House. "Voters are suspicious of centralized dictatorial type of powers - that kind of power tends to corrupt."