The semirigid vibrating rotor target (SVRT) model proposed by Zhang [J. Chem. Phys. 111 (1999) 3929] is applied to study the dynamics of dissociative adsorption for CH4 on a flat and static Ni(100) surface. The molecule CH4 is treated as a semirigid vibrating rotor CH3-H, and the London-Eyring-Polanyi-Sato potential energy surface is utilized. The numerical calculation for the reaction system is carried out by using the timedependent wave packet approach, and the propagation of wave packets is obtained by the split-operator method.The results demonstrate many important properties of the CH4 molecule dissociation process on the metal Ni.The dissociation probability is a strongly increasing function of the incident kinetic energy, and is enhanced significantly when the molecule CH4 is excited, which denotes the clear vibration-excitation effect, as observed in the molecular beam studies of Holmblad et al. [J. Chem. Phys. 102 (1995) 8255] The isotopic effect is also studied for molecules CH4 and CD4 at the ground rovibrational states.