Objective To investigate the protective effects of kaempferol against the fatty acid-induced islet microvessel endothelial function injury and the role of poly(ADP-ribose) polymerases-1(PARP-1). Methods Mouse islet microvessel endothelial MS-1 cells were divided into normal control group, solvent (DMSO) group, fatty acid group (0.25 mmol/L palmitic acid+0.5 mmol/L oleic acid), kaempferol group (50 μmol/L), fatty acid+kaempferol group, PARP-1 inhibitor (8 μmol/L BYK204165)+fatty acid group and PARP-1 inhibitors+fatty acid+kaempferol group. The changes of cell viability, apoptosis, nitric oxide (NO), nitric oxide synthase (NOS)and oxidative stress related indicators were examined in each group. Results After treatment with fatty acid, the survival rate of MS-1 cells was significantly decreased and the apoptosis rate was significantly increased (P<0.05); meanwhile, fatty acids also increased NO production and promoted the activities of the total NOS (tNOS), inducible NOS (iNOS) and constitutive NOS (cNOS) in the MS-1 cells (P<0.05). Treatment with fatty acid also significantly increased the lipid peroxidation products-malondialdehyde (MDA), while significantly decreased the levels of antioxidants, glutathione (GSH) and superoxide dismutase (SOD) (P<0.05); and it also increased the mRNA and protein expression of PARP-1, iNOS and cNOS (P<0.05). Kaempferol significantly attenuated the toxic effects of fatty acids concerning all the detected indicators (P<0.05). Moreover, pretreatment with PARP-1 inhibitor (BYK204165) for 1 h markedly enhanced the protective effects of kaempferol, and all the detected parameters were similar to those of the control group(P>0.05). Conclusion Fatty acid can directly trigger islet microvessel endothelial function injury, and kaempferol shows a protective effect against the toxicity of fatty acid. Inhibition of PARP-1 can significantly promote the protective effects of kaempferol.