The aim of this study is to explore a new method—high dose starting and low dose maintaining for PEGylated Fibroblast growth factor 21 (pFGF-21) treatment. Db/db mice were initially treated with pFGF-21 of high dose, then treated with pFGF-21 of low doses. The mice were treated with pFGF-21 at initial dose of 1.0mg/kg for 14days, then treated with pFGF-21 at maintenance doses of 0.125/0.250/0.375/0.500mg/kg for 30days. The hypoglycemic and hypolipidemic effects of pFGF-21 of different maintenance doses were compared. The pharmacological efficacy of the maintenance doses of pFGF-21 was evaluated by blood glucose levels, oral glucose tolerance test, glycosylated hemoglobin levels, insulin levels, body weight, lipid profile parameters, the mRNA expressions of glycolysis-related genes, the mRNA expressions of gluconeogenesis-related genes and the mRNA expressions of lipid metabolism-related genes. Results showed that in comparison to the mice treated only with initial dose, the treatment with pFGF-21 at maintenance doses of 0.125/0.250/0.375/0.500mg/kg exhibited favorable efficacy in lowering blood glucose levels and glycosylated hemoglobin levels, thus alleviating insulin resistance and improving dyslipidemia. However, among all of the maintenance doses, the dose of 0.125mg/kg was less effective than the other maintenance doses. These results suggest that using the treatment method of high dose of PEGylated FGF-21 in the start and low dose maintaining results in favorable control of the glycolipid metabolic balance. This study provides a new method for PEGylated FGF-21 treatment which is beneficial to promote the clinical application of PEGylated FGF-21.