Objective · To compare the gastric emptying rate in course-matched patients with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM), and to explore the impact of gastric emptying rate on premeal insulin therapy design in patients with T1DM. Methods · The gastric half-emptying time (T50) and clinical data of 16 patients with T1DM and 32 course-matched patients with T2DM treated at the Department of Endocrinology and Metabolism, Renji Hospital, Shanghai Jiao Tong University School of Medicine from September 2013 to June 2014 were analyzed, retrospectively. The T50 and clinical data of the course-matched patients with T1DM and T2DM were compared. The impact of T50 on premeal insulin therapy design in patients with T1DM was analyzed. Results · The T50 of patients with T1DM was significantly longer than that of the course-matched patients with T2DM (P=0.013). T1DM patients with delayed gastric emptying rate tended to shorten the time between insulin injection and meal than those with normal gastric emptying rate. Conclusion · The gastric emptying rates of patients with T1DM are slower than those of the course-matched patients with T2DM. Measurement of gastric emptying rate not only detects abnormal gastric emptying rate in patients with diabetes but also guides the choice of premeal insulin therapy, optimizes glycemic control and avoids large glucose fluctuations in patients with TIDM.