MARCH study suggested that acarbose had similar therapeutic effect on glycated hemoglobin reduction compared to metformin in newly diagnosed type 2 diabetes patients as initial therapy in China. We aimed to investigate whether the efficacy of acarbose was still similar to metformin under different beta-cell function status. According to the homeostasis model assessment (HOMA)-beta level, 670 patients were divided into better beta-cell function group, medium beta-cell function group and poor beta-cell function group. Patients received acarbose 300 mg/d or metformin 1,500 mg/d for 48 weeks. We found both acarbose and metformin could decrease glycated hemoglobin to similar levels after 48 weeks treatment in all groups. In medium beta-cell function group, the decrease of fasting blood glucose after metformin treatment was more significant compared to acarbose (p = 0.040); however, the decrease of post-challenge blood glucose after acarbose treatment was more significant compared to metformin (p = 0.020). Moreover, in poor beta-cell function group, the decrease of body weight and body mass index after acarbose treatment were significant compared to metformin (p = 0.004 and p = 0.031, respectively). Therefore, acarbose contributed a similar therapeutic effect to plasma glucose control compared to metformin treatment, even under different beta-cell function status.