Deborah Gore Dean, an executive assistant to Housing and Urban Development Secretary Samuel R. Pierce Jr. and a member of a prominent Maryland Republican family, has been nominated to oversee one of the department's most technical urban programs.

President Reagan nominated Dean, 33, to become an assistant HUD secretary for community planning and development, a $77,500-a-year position that handles about $3.7 billion in urban grants each year. In the past, someone with previous experience with urban redevelopment programs usually held the post.

Dean, the daughter of Louise Gore, a former Maryland gubernatorial and senatorial candidate, has held several appointive positions in the Reagan administration, but she has not worked in a local government or had direct responsibility for HUD's urban programs.

"I know them backwards and forwards," Dean said yesterday, adding she probably would know the HUD programs "as well as anyone coming in for the last 18 months of the administration."

"I have had 4 1/2 years of experience in the department right in the secretary's office on matters from the budget to congressional liaison," she said.

Dean's lack of direct experience with urban programs, however, concerned some leaders of national urban development groups.

"From our point of view, naturally, we would have preferred to have someone with hands-on experience either at the political or managerial level," said Alan Beals, executive director of the National League of Cities.

Richard Y. Nelson Jr., executive director of the National Association of Housing and Redevelopment Officials, expressed similar sentiments but said he was not surprised by the appointment, which he said had "been rumored for some time."

Nelson said his group hoped that Dean would become an advocate for urban programs, many of which the administration has urged Congress to kill.

Dean said she realized it would be unlikely she could win budget increases of the size that would keep some city officials happy, but she said she would be a "gung-ho" advocate of job development programs.

Despite the cuts, "it's still a very big program and a very responsible position," Beals said.

Dean, who received a degree in international relations in 1980 from Georgetown University, published a now-defunct magazine called City Life and later was managing editor of Encore, another Washington publication, before she joined the federal government.

According to her biography, she worked as a special public affairs and congressional assistant at the Department of Energy from 1981 to 1982, when she joined the HUD executive staff.

Her family has been active in politics since the first Gores arrived in the U.S. in colonial days on a ship called the Hawk and Dove, Dean said. Her father was active in Tennessee politics and one of her cousins, Sen. Albert Gore Jr. (D-Tenn.), is running for president.