Abstract： Objective To determinate the minimal erythema dose (MED) of adult females and to analyze the influence of age and skin color on skin photosensitivity. Methods MED was determined in 621healthy adult females in Shanghai region, and narrow-band spectrophotometer was used to detect the skin color of these subjects. The correlation between skin color and MED was assessed. Results The median MED was 39.04 in testees aged between 31 and 40 years, 24.99 in those aged between 41 and 50 years and in those between 51 and 60 years. The correlation indice were 0.366 and 0.315 between MI and MED and between EI and MED respectively in testees aged between 31 and 40 years, relatively higher than those in testees over 40 years of age. Conclusions The sensitivity of skin to ultraviolet rays increases with age, and there is a close relationship between the skin color and MED.