To investigate the polymorphism distribution of MICA gene exon 5 microsatellite in Shanghai Han population and study the relationship of MICA gene and its closely linked gene HLA B.The microsatellite polymorphism of MICA exon 5 in 175 unrelated healthy individuals were investigated using PCR-heteroduplex analysis.(1)There are 5 alleles of the microsatellite polymorphism in exon 5 of the MICA gene in Shanghai Han population, the gene frequency of MICA*A5 is the highest(39.14%), the next is MICA*A5.1(22.29%). (2)There is strong linkage disequilibrium between the HLA-B and MICA STR loci, e.g. MICA*A5 and HLA-B15, MICA*A4 and HLA-B27.The polymorphism distribution of MICA gene and the linkage disequilibrium between MICA and HLA-B have deviations in different ethnic groups.