Abstract: The impact velocity between space debris and spacecraft is normally in excess of 10 km/s. The impact process at such velocity features high temperature, high pressure and high strain rate, along with phase transitions. The vapor occur at the same time. Based on AUTODYN/SPH secondary development, Sesame EOS library and phase diagram of Al are embedded in the AUTODYN/SPH. The simulated hole diameters of bumpers are 9.02 and 9.34 mm at the impact velocities of 5.0 and 5.6 km/s. The simulation results are consistent well with the experimental results, which shows that the physical modeling and the selection of parameters are reasonable and the method of numerical simulation is correct and valid. The phase distributions of debris cloud generated by hypervelocity impact are computed, and the distribution of gas state, liquid state and solid state in debris cloud is also derived.