A 3 m diameter disc buoy was designed in order to verify the performance of the domestic meteorological and hydrological sensors. It is planned to carry out the application test of all the sensors in the sea area with a depth of more than 2 000 m. The environmental statistics of the sea area where the buoy will be deployed, such as wave height, wave period, maximum wind speed and surface velocity, are proposed. The design parameters of the buoy, such as mass, center of gravity, draft, projection area of the external force and moment of inertia, are calculated. The hydrodynamic calculation of the buoy is carried out in the frequency domain by using AQWA software based on the threedimensional potential flow theory and wave radiation-diffraction theory, the first-order wave force, additional mass, additional damping and response amplitude operators of the buoy are simulated. The buoy design scheme is optimized by the simulation results. The calculation results of the optimized buoy change smoothly with the wave frequency, The amplitude is reasonable and there is no singularity in it, the results indicate that there is no obvious resonance between the buoy and the waves in the working sea area, and the buoy has enough bearing capacity for the environmental load. The scheme can be used in the development of buoy.