Total knee arthroplasty is regarded as the most effective treatment for severe knee osteoarthritis. The influential factors of blood loss in total knee arthroplasty remain controversial. The study aims to explore the influential factors of blood loss in total knee arthroplasty comprehensively. Three hundred and four osteoarthritis patients undergoing unilateral primary total knee arthroplasty were enrolled. Demographic characteristics, laboratory results, surgical protocol, and hemostatic and anticoagulation drugs were collected. Estimation of blood loss was calculated using the Gross equation. Multivariable stepwise linear regression analysis was performed to find out the influential factors. Total blood loss reached the biggest volume (1346 ± 671 mL) in the post-operative third day. Hidden blood loss reached 465 ± 358 mL. Gender, tranexamic acid, prosthesis type, and drainage were proven to be positively correlated with the total blood loss (all P < 0.05). Male appeared to suffer more surgical blood loss than female. Posterior cruciate stabilizing prosthesis might lead to more surgical blood loss than posterior cruciate retaining prosthesis. Tranexamic acid could effectively reduce total blood loss while drainage might increase bleeding. Gender and anticoagulation drugs were correlated with hidden blood loss (both P < 0.05). Low molecular weight heparin resulted in less hidden blood loss than rivaroxaban. Posterior cruciate retaining prosthesis and topical use of tranexamic acid were preferred to reduce total blood loss. Drainage was not recommended due to the risk of increasing bleeding. Low molecular weight heparin was recommended to prevent venous thrombosis.