To investigate the genetic resources and to clarify the classification status of the Chinese yak, the Maiwa, Jiulong, Datong and Tianzhu White yak were intensively studied using microsatellite DNA, RAPD and AFLP DNA markers on the basis of our previous work on the chromosomes and blood protein polymorphisms. The overall results showed that: (1) the genetic distance based on allelic frequencies at microsatellite loci between the Maiwa and Jiulong yak was the largest (1.506) and as expected that two populations of the Maiwa yak had the smallest genetic distance (1.062). The four yak breeds were clustered into two groups, the Jiulong yak alone in a group and the rest of three breeds in another; (2) the genetic distance between the Datong and Tianzhu White yak was the smallest (0.0336) while it was the largest between the Jiulong and Maiwa yak (0.0414) based on the data from RAPD and RFLP analysis. The four yak breeds again clustered into two groups with the Datong and Tianzhu White yak grouped together first followed by the Maiwa yak; (3) the chromosome and blood protein polymorphisms analysis arrived to a similar pattern of breed relationship. Therefore it was concluded that the Chinese yak can be considered as two types with the Jiulong and Maiwa yak as their representatives, respectively. This conclusion is in concordance with the proposal by later professor Cai Li and his colleagues who classified the Chinese yak as two types of the ‘Qinghai-Tibetan Plateau yak’ and the ‘Hengduan Mountain Alpine yak’, but differs from other classifications proposed by others. Taking into account of the geographic distribution, ecological factors, history and development of the Chinese yak, we believe that this classification is reasonable.