Abstract: Detected the genetic relationship of 7 species or varieties (forma) belong to the genus Pinus including 3 species, 3 varieties and crooked P.yunnanensis, with SSR molecular marking technology in distribution regions or neighboring regions of P.yunnanensis. was 100 individuals of 7 species or varieties (forma) presented 31 alleles with 9 pairs of SSR primers. The number of alleles varied 2 to 6 with an average of 3.4 for each locus. There were high genetic diversity in P.kesiya var. langbianensis population and low genetic diversity in P.yunnanensis var. tenuifolia. Those species or varieties (forma) were classified into 3 main groups by UPGMA cluster analysis based on Nei′s (1983) genetic distance. Among them, P.massoniana and P.kesiya var. langbianensis classified as a separate group, respectively, the other 5 species or varieties (forma) clustered into 1 group. The most similar ones were found between P.yunnanensis and crooked P.yunnanensis and obvious genetic differentiation was not found. The phenotypic degeneration may be caused by the artificial negative selection or environmental degradation.