Abstract: The impulse of irregularly shaped space debris under laser irradiation was calculated, on the basis of the experimental phenomenon that reverse jetting under laser ablation is always normal to the irradiated surface no matter what the laser incident direction is. Fragments of sphere, cylinder and cube were selected as examples according to NASAs investigation of space debriss shape. The results indicate that for fragments of sphere and cube shapes, the impulse direction was along the laser irradiation direction, and their magnitudes of impulse are fixed proportional to cylindrical ones when the fragments materials were the same. For sylindrical fragments, both of the magnitude and direction of impulse change with thevariation of laser irradiation direction.