Objective To systematically review the correlation of activated partial thromboplastin time (APTT) and prognosis after ECMO treatment. Methods The PubMed, EMbase, MEDLINE, CNKI, WanFang Data and VIP databases were electronically searched to collect studies on the correlation of APTT and prognosis after ECMO treatment from database inception to April 11th, 2022. Two researchers independently screened the literature, extracted data, and evaluated the risk of bias of the included studies. Meta-analysis was then performed using RevMan 5.4 software. Results A total of 22 studies, involving 2 913 patients were included. The level of APTT in the bleeding group was higher than that in the non-bleeding group during ECMO support treatment (MD=10.34, 95%CI 1.32 to 19.37, P=0.02). The APTT level in the thrombus group was lower than that in the non-thrombus group (MD=−3.58, 95%CI −5.89 to −1.27, P=0.002). The level of APTT in the death group was significantly higher than that in the survival group (MD=8.97, 95%CI 5.89 to 12.06, P<0.00001). Conclusion The APTT level of ECMO patients is closely related to the prognosis of bleeding, thrombosis and death. Due to the limited quantity and quality of the included studies, the above conclusion needs to be verified by more high-quality studies.