Abstract: The material used in the experiment was both the large pollen gained from the male flower buds of Ginkgo biloba, which was induced by colchicines, and the normalsized pollen of G. biloba growing in Beijing. The ploidy of large pollen was determined by comparative surface morphology and DNA fluorescence content of pollen through the SEM and LSCM images of single cells. This method will benefit the identification of the larger pollen induced by colchicines, and it is easy to be used when the material is limited. The practicability of the method is better, therefore it has good application prospect in the ploidy identification of plant pollen from now on.