Abstract: The β radiation and γ radiation often exist simultaneously in some workplaces of nuclear industry. When energetic β particles and γ particles act on human body, series of reactions will be triggered in the cell. The β particles and γ particles will transfer their energy to the molecules along their tracks by ionization and excitation. Excessive energy transfered to the DNA molecule will lead to the break of the DNA chain. Besides, the β particles and γ particles can also ionize and excite water molecules in the cell. The excited water molecules can generate lots of free radicals which can react with the DNA molecule and cause the breaking of DNA chain. The track structures of particles vary with their energy. At higher LET range, track structures of particles are more concentrated, leading to more complex damages which are not easy to be repaired. So, the biologic effects caused by β particles and γ particles of different energy are not the same. Accurate measurement of β/γ spectrums is important for the radiation protection of workers. The existing mature detectors are mainly used for α-β discrimination and n-γ discrimination. The traditional secondary measurement method for β-γ discrimination has significant error because the measurement of β radiation and γ radiation can interfere with each other. Therefore, design new detector for β-γ mixed field is significant and necessary. The laminated scintillators detector has become a hot research issue in the radiation monitoring and protection due to its good ability for β-γ discrimination. In this paper, the Geant4 was used to simulate the energy deposition of β particles and γ particles in the laminated scintillators detector and the influences of material and structure on the particle discrimination performance of detector were studied. The simulation results show that for a two-layer scintillators detector, the material selection of the first and second layer has little influence on the distinguish of β particles, only affects the distinguish of γ particles. The false discrimination rate and recognition rate of γ particles increase with the atomic number of the first layer material and the second layer material, respectively. Comparing with the two-layer scintillators detector, the false discrimination rate of γ particles for a three-layer scintillators detector is significantly lower and increases with the thickness of the first scintillator. According to the simulation results, the three-layer scintillators detector composed by 0.2 mm BC-444+17.8 mm BC-444+25 mm BaF₂ has a better discrimination ability, and the corresponding recognition rate and false discrimination rate of β particles and γ particles are 96.7%, 41.1% and <0.001%, 0.16%, respectively.