A fast simulation method for obtaining space-based optical observation images of massive space debris is proposed to increase the computational efficiency of space-based optical imaging simulations of massive space debris. First, the imaging principle of the space-based optical observation images was explained. Then, an imaging simulation process was designed and a calculation method for each process was given. It is concluded that the calculation of the visibility of space debris under multiple constraints mainly limits the imaging simulation speed. Thus, an evaluation index of the influence of each constraint on the speed was established for solving the space debris visibility. Finally, based on the established evaluation indicators and the characteristics of actual observation tasks, a strategy for rapidly solving the visibility of massive space debris under multiple constraints was proposed. The simulation results show that the imaging simulation speed of the proposed method is significantly faster than the traditional imaging simulation algorithm while ensuring the fidelity of the simulation images, which is of great significance for developing and effectively evaluating the space-based visible-light observation platform.