In order to determine the shear modulus of deep sea environmental, shear modulus test system for deep-sea environment was designed. Based on the analysis to its control system, a closed-loop control strategy of pressure and temperature was proposed to simulate the deep-sea environment.Based on the principle of micro tensile test, the shear modulus tester was designed.Pressure chamber and shear modulus tester were analyzed by ABAQUS software to ensure stable operation at low temperature and high pressure. The error analysis was carried out, and frequency and displacement curve of the transducer was obtained. The results show that pressure chamber and shear modulus tester are less deformed. The shear stress-strain curve of the material is obtained. The system has high reliability and stability, which provides some reference for deep-sea environmental testing.