Gov.-elect Harry R. Hughes today nearly completed his cabinet-level housecleaning by firing four more department secretaries, thereby assuring that his own cabinet will include at most only three holdovers from the Mandel-Lee administrations.

The state bureaucrats fired by Hughes today were Herbert F. Cahan of economic and community development, Richard A. Batterton of human resources, Hermann Intemann of transportation and Y.D. Hance of agriculture.

Their dismissals bring to nine the number of cabinet officers who have been asked to leave or resigned within the last week as Hughes prepares for Jan. 17, the day he takes over the state government. According to Michael Canning, Hughes' spokesman, the cabinet changes "reflect Mr. Hughes' commitment to bring in fresh faces and ideas, not a negative comment on those being replaced."

At the same time, Canning announced that Hughes had decided to retain James Coulter, who has served as secretary of the Department of Natural Resources since 1972. Coulter and budget director Thomas W. Schmidt are the only cabinet secretaries to be reappointed by Hughes.

Of the 12 cabinet officers in the administration of Acting Gov. Blair Lee III, only one, J. Max Millstone of general services, has yet to get the word from Hughes as to whether he can stay in Annapolis for another four years.

Millstone said he met with Hughes for more than one hour in Baltimore today, and left the meeting "totally impressed" with Hughes' knowledge of his department but "totally uncertain" about his future. Millstone's uncertainty was reflected in his offer to "sleep at the office" until Hughes makes up his mind.

Millstone and his cabinet colleagues had developed a sort of gallows humor during Hughes' transition period. Most of them were certain that the new governor would want to replace them with his own people, but as week after week went by with no word on cabinet changes, some of them entertained the thought that they might be asked to stay on.

One of those fired yesterday, Cahan, went so far as to reorganize his department during the transition period, firing two key subordinates and hiring one new assistant. "I had no expectations," Cahan explained today. "But I decided to run the department as if nothing were happening around me."

Cahan said he was not sure what to do when Hughes won the election. "I didn't know whether to hand in a resignation or what," he said. "Remember, this is the first transition since Maryland took on a cabinet form of government and there was no precedent for us.I asked Harry at one meeting how we were supposed to handle it and he said he wasn't sure either."

What Hughes finally chose to do was call in all the cabinet officers last week, fire four of them on the spot and tell the others that their fate would be decided a week later -- today. This process attracted criticism from some of the department heads, who thought they were being asked to undergo a kind of torture, and from many of their aides and friends, who thought there was no reason for Hughes to even consider firing them.

In some cases, there were letterwriting campaigns for the threatened department chiefs. The Hughes transition office here received dozens of letters from farmers requesting that the new governor retain Hance, who once served as president of the Maryland Farm Bureau.

Hance said he had nothing to do with the campaign in his behalf and he seemed reconciled to his fate today. "I'm going back to Calvert County to farm 'backer (tobacco)," Hance said. "That's politics, you know."

Hughes has led a relatively cloistered existence since the November election, meeting with the press infrequently and spending most of his time in a wood-paneled office on the 15th floor of the state office building in Baltimore. He emerged earlier this week to announce the appointment of Gordon C. Kamka to head the state corrections system.

But today, when the firings were announced, Hughes was not available to answer questions. When his spokesman, Canning, was asked why Hughes decided to retain Coulter and Schmidt but drop the other cabinet officers, he responded: "He (Hughes) did not comment specifically on that."

Coulter, 59, who as DNR secretary will be most responsible for Hughes' environmental policy, has a reputation as a moderate who has attempted to balance the conflicting forces of preservation and progress. In a 1972 interview, he spoke harshly of the then-flourishing ecology movement, saying: 'Most of the current crop of so-called ecologists will be discredited and should be discredited."