Abstract: NiMgAl-LDHs/γ-Al₂O₃ was first synthesized by in-situ co-precipitation method with γ-Al₂O₃ as support, which was further transformed to the NiMg(Al)O/γ-Al₂O₃ catalyst through calcination. The NiMg(Al)O/γ-Al₂O₃ catalyst was characterized by TG-DTG, XRD, SEM, N₂ physisorption, FT-IR and CO₂-TPD and its performance in the transesterification was investigated, for the production of biodiesel with microalgae oil and methanol as raw materials. The results show that NiMgAl-LDHs and NiMg(Al)O are successfully developed on the surface and pores of γ-Al₂O₃ with high binding strength. The NiMg(Al)O/γ-Al₂O₃ catalyst exhibits high activity in transesterification; with a methanol/oil molar ratio of 12:1, the yield of biodiesel oil reaches 95% after reaction for 3 h. Moreover, the yield of biodiesel is still above 82% after using seven times.