Robert Tlyer Davis, 73, former assistant director and acting director of the National Collection of Fine Arts, died March 12 in Pasadena, Calif. He had suffered from cancer.

Mr. Davis came to the National Collection of Fine Arts in 1968 as assistant director, and was acting director for a time until 1970.

He then devoted his time to research on the European and Asian decorative objects in the John Gallatly collection at the National Collection. He also was a consultant to graduate fellows and interns.

After his retirement in 1974, Mr. Davis moved to Lily Dale, N.Y. He was visiting relatives in Pasadena at the time of his death.

Born in Pasadena, he was a graduate of Harvard University, studied at the Sorbonne in Paris and was a Carnegie fellow in Europe. He specialized in painting, sculpture and the decorative arts.

Mr. Davis had been director of education at the Albright-Knox Art Gallery in Buffalo, N.Y., and director of the Portland (Ore.) Art Museum and then the Montreal Museum of Fine Arts.

He organized and was chairman of the art department of McGill University in Montreal. He was director of Vizcaya, the James Deering estate in Miami, which he helped open as a public museum. He taught at the University of Miami, and later was a museum consultant with French and Co.

The author of "Native Arts of the Pacific Northwest" and numerous exhibition catalogs, Mr. Davis was a member of the American Association of Museums, the College Art Association of America and the American Society for Aesthetics.

He is survived by a sister, Mrs. Newton Wheeler, of Pasadena.

The family suggests that expressions of sympathy may be in the form of contributions to a memorial fund in his name at the National Collection of Fine Arts.