To investigate the semi-quantitative method for evaluating the lipid accumulation in pancreas, the KKAy mice, a classical type 2 diabetes mellitus model mice, were used and treated with rosiglitazone (Rosi); and the age-matched C57BL/6J mice were used as normal control.  Pancreas was fixed quickly for histological examination with HE staining.  For the estimation of the lipid accumulation in pancreas, semi-quantitative method was designed: the number and the size of islet, lipid accumulation in islet and in exocrine gland were observed and the integrative score calculated under the microscope, separately.  In KKAy mice, the characteristics of the increased amount of islet, the enlarged area of islet, an abundance of large vacuolations, lipid droplets, and fat proliferation were exposed frequently, and the integrative score increased 2.1 folds compared with that in C57BL/6J mice.  Meanwhile, the levels of serum glucose, insulin, and triglyceride (TG) were 1.7, 18.0, and 9.0 times as those in C57BL/6J mice, respectively.  With the rosiglitazone (10 mg·kg⁻¹) treatment, compared with that in KKAy mice, the pancreatic pathological changes were ameliorated significantly, and the integrative score in KKAy + Rosi mice decreased by 28.9%; and the levels of serum glucose, insulin, and triglyceride decreased  by 48.3%, 81.3% and 64.1%, respectively.  It showed there is a correlation between the pancreatic pathological semi-quantitative score and the values of serum parameters.  In conclusion, this semi-quantitative scoring method is simple and objective for the evaluation of lipid accumulation in pancreas of mice.