With the increasing activities of deep-sea exploration in China, the demand for various transducers, sensors and related products suitable for deep-sea acoustic sensing and testing platforms are also increasing. In this paper, a 20 MPa high-pressure anechoic tank is designed to satisfy the static pressure test within 2 000 meters of water depth, and the acoustic performance test under different water depths can be realized with the additional acoustic metering system. The tank adopts a cylindrical shell, and the covers at both ends are hemispherical. Its inner diameter is 1.5 m and the length at the central axis is 3.0 m. Two flange openings at the top of the tank are provided with a spacing of 1.0 m, which can satisfy the measurement of acoustic devices with a size up to 0.1 m. The water tank is internally equipped with Korean pine made silencing wedges. The wedge has a hollow structure, and the installed cabin has an effective inner diameter of 0.9 m and an effective length of 2.14 m (central axis). The lowest working frequency of acoustic measurement (free field reciprocity method) is designed as 10 kHz. According to the Comsol simulation results, the echo interference from 10 kHz to 58 kHz is larger than 1 dB, which means the measurement should use pulse wave method, and the transmission pulse width does not exceed the shortest sound path difference of 230 μs (sound speed: 1 500 m/s). The echo interference in the frequency band above 58 kHz does not exceed 1dB, which means continuous wave method can be used. Besides, the cabin is equipped with a rotating mechanism and an axial telescopic mechanism, which can meet the measurement requirements of different angles and distances. At the same time, it is equipped with lighting and camera to meet the needs of real-time observation. The anechoic wedge in the middle section of the cabin is designed to be detachable, and the hatch cover at one end is designed to be electrically opened and closed, so it can also meet the static pressure test requirement of large-sized equipment.