In this study, we found that STAT3 and Jagged1 are all overexpressed in platinum‐resistant ovarian cancer tissues, and STAT3 is directly regulated by the Notch ligand Jagged1, the leading to aberrant occurrence of EMT, further reinforcing the abilities of invasion and migration of cisplatin‐resistant ovarian cancer cells in vivo and vitro. The gene discussed is JAG1; the disease is ovarian carcinoma.