This paper deals with the polymorphism of male cones in the   populations of  Pinus yunnanensis Franch. from the central region of   Yunnan. The morphological characters of male cones were statistically     analyzed in the sampled populations.Male cone characters were observed   and their polymorphism was described in the populations. As a result,     male cones were shown highly polymorphic in the populations and the   polytypism between the populations was obvious in P.yunnanensis.In    the populations, the fertility, colour, number and size of male cone are   controlled by multigene,and the variation of these characters appear    continuous.The polymorphism and polytypism of male cones are based upon   the rich genetic diversity and high heterozygosity among individuals and populations of  P. yunnanensis. The heterozygous advantage and environmental heterogeneity are both important factors which cause and maintain  the balanced polymorphism and herozygosity within population. The reproducibility of male cones is correlated with the habitat and wood age,and    closely correlated to the genetic structure of individual and population of  P. yunnanensis. It is important to utilize the hybrid vigor and   heterozygous advantage in forest breeding and platation.