The distributin of C81 of phenotypes in 203 Chinese Han populations in Liaoning area were studied using the ultra—thin polyacrylamide gel isoelectric focusing (PAGIEF) follwed by immunoblotting technique. The gene frequencies were as follows; C81 0.5567, C81 0.4433, The observed numbers of the phenotypes were in agreement with the expected numbers under the Hardy-Weinberg equilibrium. The gene frequencies among Chinese and other populations were compared.