Purpose of Investigation: Heat shock protein 27 (Hsp27), a member of the heat shock protein (Hsp) family, is critical in the stress response. However, the role of Hsp27 in the pathogenesis of preeclampsia remains unknown. The aim of the present study was to examine effect of downregulation of Hsp27 in proliferation, migration, and invasion in human JAR cells. Materials and Methods: To determine their effect, siRNA interference was used to knock down Hsp27 expression in JAR lines. The effects of transfected cells were screened for HSP27 expression by Western blotting analysis. Cell proliferation determined by CCK-8 assay and cell clonogenic assay. Wound healing assay measured the migration ability. Transwell assay measured migration and invasion ability. Results: Downregulation of Hsp27 inhibits proliferation, migration, and invasion in human choriocarcinoma cell line JAR. Conclusion: The present data suggested that Hsp27 may play an important role in preeclampsia.