A dicarboxylic acid is an organic compound containing two carboxyl functional groups and are also used in the preparation of copolymers such as polyamides and polyesters . Selective oxidation of cyclohexane to dicarboxylic acids using metallic nanoparticles Co-Mn on meso silica SBA-15 substrate in the presence of molecular oxygen was performed. The catalytic performance were investigated by using various reaction conditions, such as temperature, amount of catalyst, percentage of catalyst on support, time, pressure of O 2 in order to find out the optimum conditions for the oxidation reaction of cyclohexane. Catalyst 2% Co-Mn/SBA-15 showed the highest degree of selectivity, including 82% selectivity and 18% conversion of dicarboxylic acids.the optimum conditions of reaction earned at 130 ° C, 16 bar oxygen pressure, 4h and 0.05 g catalysts.the characteristic of catalyst was determined with XRD, SEM, BET, ICP analysis and the products of reaction was characterize by GC, GC-MS and HPLC.