The abstraction reaction of H with (CH_3)_3SiH was investigated at the high levels of ab initio molecule orbital theory. The geometries were optimized at the MP2 level with 6-31G( d ) basis set, and G2MP2 level was used for the final energy calculations. The theoretical analysis provides the conclusive evidence that the main process is the hydrogen abstraction from the Si-H bond, leading to the formation of H_2 and silyl radicals; the hydrogen abstraction from the C-H bond has a higher barrier and is difficult to react. The kinetics was calculated with canonical variational transition-state theory (CVT) over the temperature range 200-1 000 K, and the theoretical rate constants match well with the later experimental values. The abstraction reaction of H with (CH_3) _3SiH was investigated at the high levels of ab initio molecule orbital theory. The geometries were optimized at the MP2 level with 6-31G (d) basis set, and G2MP2 level was used for the final energy The theoretical analysis provides the conclusive evidence that the main process is the hydrogen abstraction from the Si-H bond, leading to the formation of H_2 and silyl radicals; the hydrogen abstraction from the CH bond has a higher barrier and is difficult to react . The kinetics was calculated with canonical variational transition-state theory (CVT) over the temperature range 200-1 000 K, and the theoretical rate constants match well with the later experimental values.