The present invention discloses a xanthine derivative having the structure of the following general formula (I) or a pharmaceutically acceptable salt thereof; further discloses a preparation method for the xanthine derivative or a pharmaceutically acceptable salt thereof; and further discloses the use of the xanthine derivative or a pharmaceutically acceptable salt thereof. Through experiments of DPP-IV activity inhibition experiments in vitro, impact on glucose tolerance in normal mice and impact on blood glucose in spontaneous diabetic mice, it proves that the compounds and pharmaceutically acceptable salts thereof show good DPP-IV inhibition activity, can be applied to prepare medicines for treating dipeptidyl peptidase IV-related diseases, and more particularly, can be applied to the use of medicines for treating type II diabetes or diseases of abnormal glucose tolerance.