William Mellors Henry (Hank) Blum, 31, a Denver postal worker who was born and reared in Washington, died Tuesday at Denver General Hospital of injuries suffered in a car accident earlier that day.

A Denver police spokesman said the one-car accident occurred when Mr. Blum's car left a Denver road and struck a parking meter and telephone pole. The car then spun sideways into the plate glass window of a business, coming to rest inside the building. Police quoted a witness as saying the car appeared to be traveling at a normal speed when the accident occurred.

The police spokesman said the cause of the accident has not been determined, pending results of an autopsy.

Mr. Blum graduated from St. Albans School for Boys in 1968. He managed several sports teams at the school and was credited with helping popularize lacrosse there.

In 1972, he graduated from the University of Denver. He did post-graduate work in business administration at the Arapaho Community College in Littleton, Colo.

He worked for a Denver sports firm before joining the Postal Service in 1976. He was assigned to Denver's bulk mail center at the time of his death.

His mother, the former Virginia Henry Blum, died in 1964.

Survivors include his father, William Blum Jr., and his stepmother, Ruth M. Blum, both of Washington; a sister, Margaret L., of San Antonio; a stepsister, Mrs. David Bruce Church of Atlanta, and a grandmother, Corinne Stanton Henry of Chatsworth, Calif.

The family suggests that expressions of sympathy be in the form of contributions in Mr. Blum's name to the St. Alban's School Memorial Scholarship Fund.