Currently, the solution for obtaining the sensitivity of the particle velocity sensor is usually up to some special facilities or sound sources in order to create an environment where the acoustic impedance is known, and the sensitivities at three directions need to be obtained one by one. A method based on the nearfiled acoustic holography can compute the acoustic impedance through measuring or reconstructing the sound pressure and particle velocity without any special facility or sound source, and then obtain the sensitivity of the particle velocity sensor. This method is going to be extended to measure the sensitivity of a 3D particle velocity sensor. When the normal particle velocity is measured or reconstructed, the tangential particle velocity is also measured or reconstructed, and thus the 3D acoustic impedance can be estimated at the same time and the sensitivities of a 3D particle velocity sensor at x, y and z directions are able to be obtained simultaneously. Finally, an experiment is carried out to verify the efficiency of the proposed method.