Abstract: Horizontal starch gel electrophoresis was used to investigate the genetic relationship among seven Grapsidae species: Pachyrapsus crassipes (Grapsinae), Eriocheir japonica, E. sinensis, Hemigrapsus sanguineus, H. penicillatus, Gaetice depressus (Varuninae) and Plagusia dentipes (Plagusiinae). Twelve putative enzymk loci were examined. The average proportion of polymorphic loci and heterozygosity of the seven species were 0.167 and 0.003, 0.250 and 0.036, 0.333 and 0.062, 0.250 and 0.012, 0.083 and 0.002, 0.083 and 0.059, 0.083 and 0.002 respectively. The smallest Nei's genetic distance was 0.011, which was between Eriocheir japonica and E. sinensis . It is known that the Varuninae is near the Grapsinae and Plagusiinae is far from them from Nei's genetic distances.