Abstract: Acid phosphatase was found in dried Davidia involucrata seeds. After stratification for one year, the isospecies and activity of acid phosphatase in seeds were increased. During germination of seeds, the increases of enzyme were also found. It is clear that acid phosphatase is related to dormancy and germination of dovetree seeds. After stratification for one year, only some,seeds could germinate while the majority were still dormant. These dormant seeds could be hastened to germinate with the increase of isophosphatases by use of 50 ppm 6-BA. Seeds treatcd with 100 ppm GA₃ and 50 ppm 6-BA had more bands on zymogram of isophosphatases. Treatment of 100μM 5-Fu, 100ppm CH and 200 ppm ABA dcpressed germination of seeds and inhibited synthesis of isophosphatase.