The parallel complex reactions of H(2Sg) + CN(X2Σ+; V=0, 1; J=0)→HCN (X1 ∑+) and HNC(X1∑+ ) have been studied by using classical trajectory method. The results show that the two reactions all have not threshold energies. When the vibration state V= 0 for CN (X2∑+ ), there is not main superior product in HCN and HNC. When V=1 for CN(X2 ∑+),HCN is the more superior product. However, it has been discovered that Herschbach rule and the angular momentum rule can been all used in the reaction system, but their using ranges change with initially relative translational energies and vibration states for the reactant CN(X2 ∑+),
