This 42 y/o female was found elevated fasting blood sugar with the common symptoms of hyperglycemia including increased thirst, increased hunger, frequent urination and body weight loss and diagnosed as type 2 diabetes mellitus in June 2010. Starting from July 2010, the patient began to receive the treatment from Department of Chinese Medicine, Changhua Christian Hospital. The illnes was diagnosed as “wasting-thirst disease” with insufficiency of kidney essence, yin deficiency with dryness-heat, exuberant heat damaging qi and fluid, and lower energizer dampness-heat. According to the different stages of wasting-thirst disease, Bai Hu Jia Ren Shen Tang and Zuo Gui Wan were mainly prescribed. During the initial stage, clear heat and purge fire with replenish qi and engender fluid were the major methods of treatment followed by tonify the kidney essence to retain the efficacy. After pattern identification and treatment in traditional Chinese medicine for one more year, symptoms relieved and glycated hemoglobin decreased. The result suggested us confidently that Chinese medicine would provide better medical care for type 2 diabetes mellitus.