Compensation profile in ion-implanted GaAs has been analyzed by the simulation based on the Boltzmann transport equation. Comparing the simulations with experiments, we found that the compensation profile was originated in two types of defect distribution. One was created by deposited energy and the other was created by the implanted ions in the material. These two compensation profiles have two different energy levels, since the so-called L band splits into two peaks in deep level transient spectroscopy after annealing the sample. Based on the simulated results, we also introduced two different compensation yields of ion implantation.