When Mayor Walter E. Washington mamed him acting director of the D.C. Department of Human Resources two months ago, many observers said Albert P. Russo would be a figure-head, "someone to hold the position."

But Russo said he was wrongly cast as a "caretaker" for the $450 million year agency after Joseph P. Yeldell's suspension and said he already is making changes in key areas.

Two of Russo's initial moves, in personnel practices and DHR public relations, were directed at DHR problem areas that contributed to Yeldell's suspension by the mayor on Nov. 24.

Russo said he has halted all promotions in the 10,000 employee agency "until we can develop a departmentwide promotion policy."

Yeldell is under investigation on alltgations of favoritism and nepotism in hiring and promotion practices.

Aided by City Council budget actions, Russo also virtually has eliminated what was a growing DHR public relations office under the heading of "consumer education and volunteer services."

Ex-television newswoman Susan Triutt, who headed that office, left her $35,000-a-year job short after Yeldell, meanwhile, the council is reduced the staff of that office from 17 to four.

Last week Russo transferred the smaller staff from DHR's District Building headquarters and limited them to the consumer and volunteer duties. He has instituted weekly news conferences, an unprecedented idea in Yeldell's five years at DHR.

The former deputy director who expressed awe at the weight of Yeldell's job last summer when he ran the department for a week while his boss was in Puerto Rico, has assumed his new assignment with relish.

"We are not standing still," Russo declared last week, "a thousand and one things are going on."

Russo said he has been trying to untangle the web of problems that developed during the past five years. Most of his time last week, for example, was taken up in court fighting contempt charges resulting from a huge backlog of pending welfare applications that have not been processed on time, according to recipients.

"The mayor gave me a mandate of making sure the needs of more than 200,000 city residents who to a greater DHR) are met," Russo said. "I am devoting myself totally to addressing that committment."

Russo, who as deputy director was the highest ranking white official in a department where most top officials are black, apparently has widespread support among his subordinates, including some determined Yeldell supporters, a factor one of them attributed to his "racelessness."

"Russo is getting this staff together," a DHR supervisor said. "He has the qualities of a program administrator and a politician." Russo spoke out strongly for Yeldell when the charges of wrongdoing against him were reported.

In similar fashion, Russo last week expressed his "total personal commitment" to Mayor Washington (who demoted Yeldell) at a news conference where the mayor said his administration was under attack by the media.

Asked whether he wants the DHR job permanently, Russo said "that is the farthest thing from my mind," but some Yeldell allies believe he is campaigning for it.

"Most people (in DHR) feel that Yeldell is not coming back and is not needed to come back, and that nobody, including Russo can run this mess he created," a DHR official said.

The same thought was implicit in actions by the mayor and City Councilman Sterling Tucker last month to begin the dismantling, or at least a major overhauling of DHR.

Russo, as one of his first assignments, was asked by the mayor to design changes for the problem-plagued department he inherited.

Russo said he gave the mayor last week a plan for "realignment and delegation of authority in DHR." Russo would not discuss the details of his plan, or the extent of changes he recommended. District Building sources said that he gave the mayor a revised 1975 Yeldell proposal, calling for extensive reductions in the DHR director's powers.

Russo's plan would have the authority in the department shifted to four commissioners - one each for mental health, social services, rehabilitation and health - who would have significant autonomy in operating their programs, the sources said.

The present DHR structure includes five administrators for major programs with most of the planning, budget and federal government liaision responsibilities immediately under the director.

"This system led to squabble, delays and buck-passing. A bureaucrat who knows how to sustain himself could sit back for years and do nothing and nobody could blame it on him."

Some DHR administrators agreed that there is a need for diffusion of power within the department, although they said they have not been consulted on reorganization plans.

"If there is a move afoot to break it up, then mental health should come out," Dr. Jefferson McAlpine, DHR's mental health administrator said. "All administrators would like a little more authority as far as budget and resources."

Both social rehabilitation administrator William Barr and McAlpine agreed, however, that caution is necessary in reorganization moves.

"I strongly urge that on the executive and legislative sides they stop and evaluate these programs and why DHR was organized in the first place," Barr said. "There were sound reasons for a one-department concept, and they should consider the history of the concept."

The DHR concept has merits, McAlpine said but "it cannot be run with a rigid authoritarian hand."

"The employees have accepted and feel it is necessary that the department be broken up. I know of no one who is against that," a middle-level manager said. "The table is already set," by the Council's vote last month to give autonomy to D.C. General Hospital, the largest DHR institution, he said.

Russo said he is, meanwhile, "taking one day at a time" and "trying to see that we not only keep the wheels turning but that we negotiate all the bends."

As for the attitudes of DHR workers, Russo said there were some who "felt bad about the fact that (Yeldell) is no longer acting as director, but they have begun to adjust to reality."