Objective To evaluate the significance of the prenatal diagnosis indications for prenatal cytogenetic diagnosis. Methods Fetal chromosomal karyotypes were examined in 940 pregnant women by amniocentesis. Results 928 cases were cultured successfully in 940 cases with the successful rate of 98.72%. It was shown by karyotype analysis that 26 fetuses(2.80 %) were found with abnormal karyotype,and 42.31% of which were trisomy. The risk(1.94%,6/310) of the fetus with abnormal number of chromosome in the pregnant women aged over 35 years was higher than that(0.65%,4/618)in the pregnant women aged under 35 years(P = 0.037). The determination rate(0.69%,3/432) of the fetus with high risk for 21-trisome in the pregnant women aged under 35 years was higher markedly than that in common population. Conclusion The effectiveness for prenatal cytogenetic diagnosis can be increased with proper application of prenatal diagnosis indications.