Abstarct: In this project, the natural diatomite was used as catalyst support due to its low cost, high abundance, porous structure, low density, and high surface area. The diatomite was functionalized with (3-Aminopropyl)trimethoxysilane (MSPA) and Salicylaldehyde. Then, the compounds were used to support the VO(acac)2 and MoO2(acac)2 complexes. The prepared compounds were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) analysis, scanning electron microscopy (FE-SEM), inductively coupled plasma atomic emission spectroscopy (ICP-AES), energy-dispersive X-ray spectroscopy (EDS), and surface area (BET) techniques. Furthermore, the prepared compounds were used as heterogeneous catalysts for the epoxidation of alkenes and the effects of various parameters such as the solvent, catalyst and oxidant, temperature, and time on this reaction were studied. The results show that the compounds have high catalytic activity for the epoxidation alkenes in 1,2-dichloroethane in the presence of tert-butylhydroperoxide (TBHP).