Harold W. Lady, 71 retired economic consultant and former government official, died of cardivascular collapse Friday at Suburban Hospital in Bethesda.

Mr. Lady worked in the Office of the president under Franklin D. Roosevelt then worked as the Army Air Force's chief of audit during World WAR II.

Following the war, he worked as a private consultant, served as an economic consultant to Korean President Syngman Rhee from 1948 to 1950 and again from 1955 to 1956, before becoming a vice president of Reed Research, a Washington electronics consulting firm.

Mr. Lady joined the office of the secretary of the Interior in 1963, retiring nine years later as associate director of the office of Survey and Review.

Since that time he had worked as a business and economic consultant and was a member of Lloyds of London.

Mr. Lady was born in Columbus, Ohio, and reared in Washington. He was a graduate of Eastern High School and a 1928 graduate of Syracuse University.

He joined the government in 1929, then spent two years in the early 1930s as acting comptroller for the old Agricultural Adjustment Administration in the Philliphines. He also worked for the Commerce Department before World War II.

Mr. Lady was a member of the American Institute of Certified Public Accounts. He belonged to the University and Chevy Chase clubs. He was a member of the Royal Asiatic Society and a trustee of the Center for the Study of the Presidency.

The Republic of Korea named Mr. Lady an honorary citizen in 1968 for his contributions to that country.

He is survived by his wife, Elaine, of the home in Chevy Chase; a son, Donald S., of Flagstaff, Ariz; a daughter, Diana L. Dougan, of Salt Lake City; a brother, David F., of Washington; a sister, Grace L. Brearket, of Boca Raton, Fla., and four grandchildren. CAPTION: Picture, HAROLD W. LADY