Gene Baroni, an activist Catholic priest who had led a nationwide fight to save and revitalize urban ethnic neighborhoods, will be appointed assistant secretary for consumer affairs at the Department of Housing and Urban Development.

Baroni said that HUD Secretary Patricia Roberts Harris notified him yesterday that President Carter will forward Baroni's nomination to the Senate for a confirmation vote, subject to pro froma background and security checks by the White House.

Reflecting Baroni's interests and what Harris apparently sees as a new emphasis at HUD, "neighborhood development" will be added to Baroni's formal title. His position will be known as assistant secretary for neighborhood development, consumer affairs and regulatory functions.

If confirmed, the 46-year-old community organizer and advocate for low and moderate-income ethnic city-dwellers will be responsible for formulating housing policies for the elderly, the handicapped and American Indians.

Baroni will also have charge of HUD's interstate land sales office, which regulates the sale of lots in retirement and second-home communities, and HUD's division of mobile home standards.

It was not clear yesterday what role Baroni will play in formulating HUD's urban policies. They traditionally have been the responsibility of the assistant secretary for community planning and development and Robert C. Embry Jr., Baltimore's housing comter administration.

Embry and Baroni have worked together in Baltimore and share the view that neighborhoods are the key to successful revitalization of cities.

They presumably will work together in shaping what may emerge as a more activist involvement by HUD in trying to stem the decline of the nation's cities.

During the Nixon and Ford administrations, HUD's urban policy consisted mainly of giving billions of dollars in community block grants, which cities then spent as they saw fit. While the Carter administration will continue block grants, it has asked Congress for $400 million to be used for "innovative" programs in cities that are in acute trouble.

This $400 million should give Embry and Baroni an opportunity to try to solve some urban problems and stem middle-class flight from the cities to the suburbs.

Baroni is president of the National Center for Urban Ethnic Affairs, a Washington-based nonprofit corporation that relies on foundation support and government research contracts for its annual budget of more than $1.7 million.

Baroni has organized neighborhood groups in 45 U.S. cities.

Besides Baroni and Embry, the administration is reliably reported to have decided on these persons to fill high-level HUD positions.

Jay Janis, a vice president of the University of Massachusetts (under secretary); Lawrence B. Simons, a New York City builder, (assistant secretary for housing production and mortgage credit); Ruth T. Prokop, a Washington, D.C., attorney (general counsel).

Also, Donna E. Shalala, former treasurer of the Municipal Assistance Corp. in New York (assistant secretary for policy development and research); Harry K. Schwartz, a Philadelphia attorney who was active in the Carter campaign (assistant secretary for legislative affairs).

Also, Chester C. McGuire, a Berkeley, Calif., businessman and assistant professor of regional science (assistant secretary for fair housing and equal opportunity); and Arch Parsons, a former reporter and presently public information officer at the Appalachian Regional Commission (assistant to the secretary for public affairs).