This manuscript presents a model and simulation of the copper chalcopyrite semiconductor CuGaSe2 in order to predict its magnetic properties. In the semiconductor material CuGaSe2 (CGS), the atom Cu is the only magnetic element with a magnetic moment value S = 1/2. We propose a Hamiltonian to calculate the energies corresponding to different configurations of the system. In a first step, we presented the magnetization behavior by using the Monte Carlo simulations (MCS). The magnetizations as a function of the temperature, the exchange coupling have been studied and discussed. We have also deduced and studied the magnetic susceptibilities. To complete this study, we have established and discussed the magnetic hysteresis loops of the studied compound. Finally, we have calculated the corresponding critical exponents and compared them with the standard 3D Ising model.