Abstract: There are two traditional views about the processes that maintain B chromosome polymorphisms in populations at present,which are the parasitic model and the heterotic model.Recently Camacho et al,proposed the polymorphisms of Bs is changing and developing.The primary analysis of Bs in natural diploid populations of Allium wallichii Kunth at Liangwang mountain found that the number of Bs in roots of plants is constant and mostly 1-2.The statistic analysis showed that the frequency of Bs is significantly positive correlated with altitude but respectively there is no significant effect between Bs and tiller,fresh weight,flowers of A.wallichii.The adaption of Bs in population of A.wallichii was discussed and Bs of A.wallichii often existing at relatively adverse environment is adversed.