High Throughput Sequencing (HTS) is a feasible approach for characterizing T-Cell Receptor (TCR) repertoire, and this technology has been applied in various diseases. For a pregnant woman, immunologic balance may be interrupted when the foetus grow up. How to adjust the mother’s immune system and what’s the difference before and after pregnancy are limited known. Herein, we use the multiplex PCR method to amplify TCR-β repertoire for both pregnant women and non-pregnant women. Total 12 samples are sequenced by HTS which produce on average 6.43 million sequences for each sample. We observe that the repertoire diversity and CDR3 number tend to decline slowly in gestation period. The content of high-frequency is found remarkably expended at the second trimester and then shrunken at the third trimester. Pregnant samples are clustered together and non-pregnant samples are clustered to another group using both V genes and V-J pairings. Furthermore, seven V genes which are significantly different between two groups are identified. Finally, high-frequency clones of a pregnant woman are visualized among three time-point pregnancies. Our study can provide new insight into understanding the immune response during the pregnancy, and the repertoire characteristics would provide a reference for other investigators.