Objective To explore the value of noninvasive prenatal testing（NIPT）in detecting chromo⁃somal abnormalities in pregnant women of different serological screening risk values and different ages and to pro⁃vide reference for the clinical application of laboratory screening technology. Methods A total of 11517 singleton pregnant women who underwent early serological screening and NIPT were analyzed retrospectively. According to the age of pregnant women and the results of serological screening and NIPT，the subjects were divided into different groups. For pregnant women with high risk of serological screening and abnormal results of NIPT，further prenatal diagnosis was recommended. Results With regard to the high risk rateor the critical risk rate of serological screening or the positive rate of NIPT，the elderly group was higher than those of the younger group. The positive

predictive value（PPV）of trisomy 21 and trisomy 18 detected by NIPT（84.62%，33.33%）was significantly higher than that of serological screening（42.86% ，28.57%）. The PPV of trisomy 21 and trisomy 18 in different age groups was not statistically significant. However，compared withserological screening，the abnormal results of NIPT could suggest additional chromosomal diseases. Conclusion NIPT could effectively reduce the missed diagnosis of serological screening and effectively prevent chromosomal diseases.