A method for using thymosin -10 for cancer treatment by expressing thymosin -10 in solid malignant tumor cells. More precisely, the present invention relates to a cancer treatment method wherein thymosin -10 is expressed in solid malignant tumor cells by infecting adenovirus including thymosin -10. The gene therapy for cancer using thymosin -10 of the present invention is very effective for the treatment of ovarian cancer, cervical cancer, stomach cancer and lung cancer.