Objective To evaluate the effect of short term continuous subcutaneous insulin infusion (CSII) treatment on plasma glucose and beta cell function in newly diagnosed type 2 diabetic patients with severe hyperglycemia. Methods Thirty six newly diagnosed type 2 diabetic patients with FPG>11.1 mmol/L were treated by 2 weeks CSII. An intravenous glucose tolerance test (IVGTT) was performed before and after CSII. Fasting plasma glucose (FPG), 2 hours postprandial glucose (2 hPG), glycosylated hemoglobin A 1c (GHbA 1C ), proinsulin, lipid profiles, insulin, and C peptide during IVGTT were measured. The results of FPG, 2hPG, GHbA1C, first phase insulin secretion, the mean area under the curve (AUC) of insulin and C peptide, proinsulin, proinsulin/insulin ratio, Homa β and Homa IR were compared. Results The excellent control of FPG and 2hPG in 35 out of 36 patients were achieved stably in 2.7±1.9 days and 8.5±3.5 days by CSII. After 2 weeks CSII intensive treatment, beta cell function was dramatically improved: the first phase insulin secretion of most patients was restored in different degrees, the sharp peaks of insulin release were seen in some patients. The mean AUC of insulin and C peptide and Homa β were significantly increased; plasma proinsulin, proinsulin/insulin ratio and Homa IR were decreased. Conclusion The excellent glycemic control and improvement of beta cell function can be induced by short term CSII intensive therapy in newly diagnosed type 2 diabetic patients with severe hyperglycemia.