Abstract： Ovarian vein thrombosis (OVT) is a rare, insidious and dangerous disease mostly occurs in the postpartum period. Early diagnosis and timely treatment are very important and may avoid serious complications. Here we reported a woman who had a fever and left back pain three days after vaginal delivery. Enhanced CT suggested that thrombosis occurred in the left ovarian vein, and even the renal vein was involved. Thrombus susceptibility gene detection revealed that the plasminogen activator inhibitor-1 gene was 4G/5G heterozygous genotype and the 5,10- methylenetetra-hydrofolate reductase gene was C/T heterozygous genotype. Anticoagulant treatments with low-molecular-weight heparin and rivaroxaban were effective.