LOS ANGELES, May 12— David Whitmire Hearst, a son of William Randolph Hearst and a vice president of the Hearst Corporation, died today. He was 70 years old.

Mr. Hearst, who died of cancer at Cedars-Sinai Medical Center, joined the Hearst Newspapers in 1936 as a police and city hall reporter for The New York Journal-American.

He soon moved to The Baltimore News-Post where he served as assistant advertising director before returning to the editorial desk as the paper's city editor.

In 1938 he went to The Los Angeles Herald-Express where he rose to publisher in 1950.

After retiring from the paper in 1960, Mr. Hearst continued with the Hearst Corporation as vice president and member of the board.

He is survived by his twin brother, Randolph A. Hearst, chairman of the Hearst Corporation and president of The San Francisco Examiner; another brother, William Randolph Hearst Jr., editor-in-chief of Hearst Newpapers and chairman of the corporation's executive committee, and a nephew, William R. Hearst 3d, editor and publisher of The San Francisco Examiner.

David Hearst