Abstract:Ginkgo ( Ginkgo biloba L. ) is a famous gymnosperm species, originated from China and known as "living fossil". Western blotting analysis has proved that actin also exists in ginkgo pollen like in angiosperm, but its content was only about one sixth as much as that of maize (Zea mays L. ) pollen based on the densitometry of SDS polyacrylamide gel electrophoresis. Assay on actin inhibition of DNase Ⅰ activity demonstrated that actin content of maize pollen was as about 7 times as that of ginkgo pollen. The plausible relationship between the actin content and the evolution of plant kingdom was discussed.