Abstract: Allozyme was investigated using the assay of vertical slab polyacrylamide gel electrophoresis in Scylla serrata．Eleven enzymes presum ably encoded by 22 allozyme loci and 30 alleles are scored in S．serrata，the monomorphic loci with one alide are Ldh-1，Sod-2，Aat-l，Aat-2，Skd-l，Skd-2，Idh-l，Sdh-l，Adh-l，Me-l，Me-3， Mdh-l，Amy-l，Amy-2．amd Amy-3;and 7 loci with 2～3 alleles are polymorphic，they are Est-l，Est-2(the monomorphic locus in Xiamen population)，Est-3，Sod-l，Me-2，Mdh-2(the polymorphic locus in Xiamen population)，and Mdh-3．S．serata in six samples shares nlost common alleles in all1oci，their biochemical genetic are very similar．