Blood loss after total knee arthroplasty (TKA) is a potentially serious medical problem since it leads to anemia, increased need for transfusion, and prolonged hospitalization. Some studies have reported that sealing of the intramedullary femoral canal during TKA may decrease postoperative blood loss. The purpose of this study is to determine the effects of sealing of the intramedullary femoral canal during TKA on blood loss and transfusion rate. Electronic databases, PubMed, EMBASE, the Cochrane Library, Web of Science, and Chinese Biomedical Database, were systematically searched. Only randomized controlled trials (RCTs) that compared the sealing group with the control group during TKA were included up to March 2019. Two reviewers independently extracted data and assessed the quality of included studies. The statistical analysis was performed by using Review Manager 5.3 software. Cochrane Risk of Bias tool was used for quality assessment. Overall, eight RCTs involving 996 patients met our criteria and were analyzed. The results of meta-analysis showed that patients in the sealed group had less total blood loss, less total drain output and less hidden blood loss, less transfusion rates, a lower drop of hemoglobin level at day 1 postoperatively, and less hematoma than the control group. On the other hand, there were no significant differences in infection, deep vein thrombosis, and redness of incision between sealed and control group. Current meta-analysis found that sealing the femoral canal during TKA was an effective method for the control of blood loss.