In allusion to the problems in anti-seismic measures for the crest of earth and rockfill dam, a new kind of seismic strengthening measure has been put forward with the Hardfill materials. The rigid-body limit equilibrium method and dynamic finite element method were used to calculate and analyze the effect of Hardfill seismic strengthening measure in high rockfill dam. Improvements on the stability of dam against sliding, permanent deformation and dynamic strength of materials had been discussed using the Hardfill aseismatic reinforcement. In addition, adverse effects of Hardfill were studied by calculating the acceleration, stress and deformation of the dam. The results indicate that the Hardfill reinforcement will enhance the overall stability, inhibit permanent deformation significantly, and improve the dynamic strength safety coefficient, without adverse effect to the operation of the dam.