Coronavirus disease 2019 (COVID-19) caused a global pandemic and high mortality in the last 3 years. Venous thromboembolism (VTE) was common complication in patients with COVID-19. SARS-CoV-2 infection caused cytokine release, immunocytes activation, and procoagulation cascade activation. These contributed to endothelialitis and vascular injury, and affected the coagulation system and caused coagulopathy. Studies have observed that antithrombotic treament in patients with COVID-19 might decrease ratio of organ support and improve survival. However, the optimal regimens, dosage, and duration of anticoagulation for COVID-19 remains unclear. Therapeutic dose anticoagulation was recommended in non-critically ill patients with COVID-19 who have low risk of bleeding according to recent guidelines. As risk of VTE was more complicated in critically ill patients with COVID-19, anticoagulation treatment was more challenging in these patients. At the early stage of COVID-19, increased anticoagulation intensity was recommended. However, no confirmative evidence of the benefit of therapeutic anticoagulation for critically ill patients with COVID-19 has been found. Emerging clinical trials have suggested that therapeutic dose anticoagulation was not superior to standard-dose anticoagulation. In this review, we summarize new insights into the risk factors, mechanisms, and use of anticoagu-lants in patients with COVID-19