As one of the important phenomena in nuclear physics, the principle of beta ray absorption experiment is widely used in production and medical fields. However, due to the limitations of specific experimental conditions, it is difficult to carry out relevant physics experiments in the universities. The beta ray absorption experiment process is simulated and developed by Monte Carlo calculation software Geant4. By Monte Carlo simulation method and 3D simulation technology, the characteristics of beta ray absorption is studied in the 3D simulation environment. By analyzing the absorption data of aluminum absorption plates on 137Cs radiation sources, it is found that the absorption coefficient method is closer to the theoretical value compared to the maximum range method. The energy loss per unit mass thickness is greater with the greater atomic number of a material. The virtual simulation of beta ray absorption enables the students to understand the absorption law of beta ray. At the same time, it cultivates the students' operational capacity and innovative thinking.