Objective To explore the expression of resistin-like molecules-a (RELMa) in atherosclerotic plaque of ApoE-/- mouse, and to study the effects of RELMa on the proliferation and migration of vascular smooth musclee cells (VSMCs) . Method Nine ApoE-/- mice and nine C57BL/6J mice were fed with high fat diet. All mice were sacrificed 24 weeks after force feeding. Vessels were dissected from to abdominal aorta. Sections of aortic tissue were stained with HE dyeing and RELMa in aortic tissue was assayed by immunohistochemistry. The expression of RELMa mRNA in vessels was detected by RT-PCR. The effects of different concentration RELMa in different concentrations on the proliferation and migration of VSMCs were detected. Data was expressed as mean ± standard deviation. ANOVA were used for comparison in SPSS 11.0, and changes were considered as statistically significant if P value was less than 0.05. Results Atherosclerosis plaque formed in aortic root of ApoE-/- mice after they were fed with high fat diet for 24 weeks. RELMa protein and RELMa mRNA were found by immunohistochemistry and RT-PCR in atherosclerotic plaque of ApoE-/- mouse. RELMa protein didn't be found in vessels of control mouse. RELMa promoted the proliferation of VSMCs (RELMa groups: 2811. 21 ± 216. 89,4056. 87 ±220.65,5061.45 ± 335.86, vs. control 1609.58 ± 203.53, P < 0.01). RELMa promoted the migration of VSMCs (RELMa groups: 130.54±12.98,158.39±11.58,203.50± 17.37 vs. control:70.54± 11.92, P<0.01).Conclusions RELMa expresses in atherosclerotic plaque of ApoE-/- mouse. RELMa enhances the proliferation and migration of VSMCs of aorta.