C4 haplotypes of 93 unrelated families of Han nationality in Hubei Province were determined by means of a method established in our laboratory based on the techniques recommended in the 4th International Workshop for the Genetics of Complement and the method of Carboxypeptidase B developed by Zhang in Australia. 310 C4 haplotypes were analysed. The haplotype frequency of A3B1 (0.4194) was found to be the highest in Han nationality of Hubei in China. The others are as follows: A3B2: 0.1161, A2B1 and A4B2: both 0.0903, AQOB1: 0.0645, A3BQO: 0.0548, AQOBQO: 0.0322, A2B2: 0.0256, A4B1: 0.0161, A2B92: 0.0129. Some kinds of rare haplotypes were also discovered. Significant positive-linkage disequilibrium parameters (delta) were found in haplotypes of A4B2, AQOBQO and A2B92, while the significant negative delta was observed in that of A4B1 and AQOB2. Our data were compared with those of Japanese, Caucasian in USA and Germany, Negroids in South Africa are discussed in the paper. The differences among them.