Mayor Marion Barry, beginning his second term, has significantly restructured the city's administration in a way that, if fully implemented, could affect virtually all dealings by residents, businesses and bureaucrats with the government.

In place of a strong city administrator who has had ultimate responsibility for almost all areas of the government, Barry has appointed three deputy mayors who will divide responsibilities under three broad areas.

Current City Administrator Elijah B. Rogers has been named deputy mayor for operations; until his planned departure from city government in May, he will continue to oversee the city's day-to-day operations.

Ivanhoe Donaldson, the mayor's closest political adviser and campaign manager, has been named deputy mayor for economic development, a post overseeing several, now scattered, agencies, including housing, employment services, business and economic development, office of planning and the Minority Business Opportunity Commission.

Barry named Alphonse G. Hill, the city controller in his first term, as deputy mayor for financial management. Hill, who has played a background but important role in managing the city's continuing cash flow problems, is expected to serve as a major spokesman to Congress and the press on the city's financial affairs.

Gladys W. Mack, who won credit before Congress as Barry's budget director, has been switched to the mayor's staff as a policy adviser. Officials have mixed opinions on how powerful a role she will play in the new post.

Mack was replaced as budget director by Elizabeth Raveal. Other appointments include Pauline Schneider as director of the Office of Intergovernmental Relations, the city's lobbying arm to Congress that formerly was headed by Barbara Washington.

Barry has said the changes, which included demoting or replacing several officials, such as former recreation director William Rumsey, who now is an adviser to the mayor, will give his administration a fresh start and will streamline some of the city's operations.

City officials contend that establishing the new administration would not increase the costs of government because other positions and offices will be abolished or absorbed in new agencies.

Some of Barry's appointments, including all of the department heads, will have to be confirmed by the City Council. The three deputy mayors and some other officials are not subject to such confirmation, however, administration officials said.

In addition to the change in officials, Barry's reorganization includes plans to establish a new Department of Consumer and Regulatory Affairs, which would combine for the first time a broad range of licensing, housing and permit functions.

Barry said the agency, if approved as expected by the council later this year, would be headed by Carol B. Thompson, now head of the smaller Department of Licenses, Inspections and Investigations.

Some major department heads reappointed to their jobs were Maurice Turner, chief of police; Judith W. Rogers, corporation counsel; James Buford, director of human services; William B. Johnson, director of environmental services; and Matthew Shannon, director of the Department of Employment Services.

Dwight S. Cropp, who has served as executive secretary to the mayor and the city government, is remaining in the post, which oversees the legal administration of the mayor's office and processing of official documents. Cropp's title has been shortened to secretary of the District of Columbia.