Density functional theory is used to study the CH₃+H₂ reaction mechanism, based on the group level of the B3LYP/6-31G^*, 6-311G^**, 6-311++G^**, and cc-pvtz, the CH₃+H₂→CH₄+H reaction, including reaction intermediates, transition states, and product geometries, are optimized in order to calculate the energy, at the same time the vibration analysis is carried out. The results show that the selection of the basis set does not affect stationary points geometries; the barrier 39.61kJ/mol calculated at the 6-31G^* level is consistent with the 39.41kJ/mol of experimental value; there is a j vibration mode guiding reaction process on the reaction pathway, the vibration interval is in the range of -0.57 to 0.60 amu1/2Bohr.