Bertha May Smith Barnett, 91, who was closely associated with international YMCA work, died of pneumonia Monday at Arlington Hospital.

Her husband, Eugene Epperson Barnett, at one time head of the YMCA in the United States and Canada, died here in 1970.

Mrs. Barnett went to China with her husband shortly after their marriage in 1910. They lived in Hangchow for 11 years. An accomplished pianist, she taught music and Sunday school there and formed a number of choral groups.

The Barnetts then were assigned to Shanghai for 15 years, where she assisted her husband in YMCA work and was active in community and church affairs.

The family retruned to this country in 1936 and lived in White Plains, N.Y., while Mr. Barnett was general secretary of the YMCA of the United States and Canada. After his retirement, they moved to Arlington in 1956.

Mrs. Barnett was born in Jaser, Fla. She attended Meridian Junior College in Mississippi, Virginai Southern College in Roanoke, and the Cincinnati Conservatory of Music.

She is survived by three sons, Robert W., of Washington, Henry Dewitt, of Hongkong, and A. Doak, of McLean; a daughter, Eugenia Schultheis of Arlington; a brother, Frank A. Smith of Atlanta; a sister, Esther Smitt of Clayton, Ga., 13 grandchildren and four great-grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to Walker Chapel United Methodist Church in Arlington.