Toona sinensis extract for suppressing the proliferation and inducing apoptosis of osteosarcoma, but not normal human osterblasts. The extraction process comprises: extracting Toona sinensis with water to obtain a first extract, and filtering the first extract by a membrane to obtain a filtrate, and the Toona sinensis extract of the invention does not cause biological damages of normal bone cells. In addition, the invention further provides a pharmaceutical composition comprising the Toona sinensis extract.