In order to realize the simulation measurement of seabed sediment in situ environment,the seabed environment simulation triaxial compression system was designed.Through the three pressure units of confining pressure,back pressure and axial pressure,the water depth pressure,buried depth pressure of seabed sediments were simulated.The mathematical model of the hydraulic pressurization unit was established,and the bulk elastic modulus of water under different conditions was obtained through the secant bulk elastic modulus equation of the water medium.The effect of different temperature,pressure and seawater salinity on the pressurization performance of the pressurized system was studied.After analysis and test,it is concluded that the influence of temperature change per 1 ℃,pressure change per 1 MPa,and salinity change per 1‰ on the compression performance of the pressurized system is 0.36%,0.14%,and 0.21% respectively.By simulating the elastic modulus change of water volume caused by environmental fluctuation,the 0.6 MPa pressure disturbance changes in the test bin,and the adjustment time for the system to automatically restore the stable state should not exceed 5 s.The experiments show that the overshoot of the system is less than 0.05 MPa,and the test pressure fluctuation within 10 min from 1 MPa to 10 MPa does not exceed ±0.005 MPa.The system pressure control characteristics and anti-interference performance are good,meeting the measurement requirements.