Abstract: The polymorphisms of 4 serum protein loci，prealbumin （PA），esterase （ES），amylase （AM）and alkaline phosphatase （AKP） of 26 Banna miniature pigs were investigated by using the method of vertical polyacrilamid gel electrophoresis （PAGE）. The genotype frequencies, gene frequencies and indexes of genetic diversity were calculated. The results showed that the prepondant genes of the above-mentioned 4 loci were PA^B，ES^s，AM^A and AKP^c,the indices of genetic diversity of them were 0. 2603，0.4970，0.3551 and 0.2042 respectively；and the ration of homozygosities at each locus were relatively higy.