Objective：This study aims to identify the peptide with different expression in preeclamptic placenta by liquid chromatography-tandem mass spectrometry（LC-MS/MS），and to study the bio-active function of the differentially expressed peptides. Methods：Placental tissues were collected from 4 normal pregnant women and 4 pregnant women with preeclampsia. All participants underwent planned cesarean section in the Department of Obstetrics，the First Affiliated Hospital of Nanjing Medical University from May 2019 to September 2019. The effects of the differential peptide 405SPLFMGKVVNPTQK418 on the proliferation and migration of trophoblast cells（HTR-8/SVneo） were studied by CCK-8 assay，clone formation assay and transwell assay. And the matrigel assay was used to study the effect of this peptide on the angiogenesis ability of human umbilical vein endothelial cells（HUVECs）. Western blot was used to detect the metalloproteinase 2 （MMP2） and metalloproteinase tissue inhibitor 1 （TIMP1） in peptide-treated group and control group. Results：A total of 3 582 peptides were screened out and 48 differentially expressed peptides were identified. In vitro functional assays showed that the differential peptide 405SPLFMGKVVNPTQK418 could promote the proliferation and migration of trophoblast cells and the tube formation ability of endothelial cells. After peptide treatment，the expression of MMP2 was up-regulated and the expression of TIMP1 was down-regulated. Conclusion：A series of differentially expressed peptides were detected in preeclamptic placenta，and the differential peptide 405SPLFMGKVVNPTQK418 exhibited a promotive role in the behaviour of trophoblast cells and endothelial cells，which provides support for the study of pathogenesis and treatment of preeclampsia.