Abstract: Objective A multicenter, randomized, opened and controlled clinical trial was performed to compare the efficacy and safety of Gansulin 50R and Novolin 50R in type 1 and type 2 diabetes. Methods 480 cases were randomized into two groups(3∶1)treated with Gansulin 50R versus Novolin 50R for 12 weeks respectively. Results Compared with pretreatment,at the end of 12 weeks’treatment,the decreased values of HbA1c(0.91% vs 0.94%), FPG(1.56 mmol/L vs 1.61 mmol/L) and 2hPG(3.35 mmol/L vs 3.53 mmol/L) were all proved significantly in both Gansulin 50R group and Novolin 50R group(all P<0.05). And the changes of HbA1c from baseline to endpoint were similar between the two treatment groups (P>0.05). Overall, all adverse events,including hypoglycemic events and the incidence of nocturnal hypoglycemia were similar between both groups(P>0.05). Conclusions Gansulin 50R and Novolin 50R have similar efficacy and safty profiles in the treatment of diabetic patients