The invention provides a pharmaceutical composition for repairing wounds and a preparation method thereof. In the method, no additional commercially available synthetic thrombin or non-human thrombin is added, while blood can be directly prepared into the pharmaceutical composition for repairing wounds. The pharmaceutical composition for repairing wounds provided by the invention can avoid rejection reaction of patients, moreover, the method provided by the invention can be used for preparing the pharmaceutical composition in a large scale to reduce the manufacturing cost, in order to reduce the medical treatment cost and relieve the burden of patients.