The antidiabetic properties in silkmaterials, such as silkwormand silk fibroin, have been described in traditional folk medicine. In a previous study, we reported that the silk fibroin hydrolysate (SFH) had a protective effect against glucotoxicity in HIT-15 cells and an antidiabetic effect in a noninsulin-dependent diabetes mellitus (type 2 diabetes, T2DM)mouse model. This study aimed to determine whether SFH ameliorates diabetic dyslipidemia and promotes pancreatic ${eta}$-cell function in a T2DM animal model ($C57BL/KsJ^{db/db}$). SFH significantly improved blood glucose levels after 4 weeks of treatment. T2DM animals had a normal serum blood glucose level after 6 weeks of SFH treatment. Hemoglobin $A_{1c}$ (HbA1c) levels were significantly lower in T2DM animals that were treated with SFH for 6 weeks. Glucose tolerance in T2DM animals also significantly improved after 6 weeks of SFH treatment. Furthermore, plasma total cholesterol, high-density lipoprotein cholesterol, nonesterified fatty acid, and triglyceride concentrations significantly decreased in SFH-treated T2DM animals compared to T2DM animals. This result showed that SFH ameliorated diabetic dyslipidemia in the T2DM model mice. Taken together, our results suggest that SFH could be used as a potential agent to treat dyslipidemia in patients who have type 2 diabetes mellitus.