Abstract: In the airborne sound field, the particle velocity sensor with the feature of figure-of-eight directivity independent of sound frequency is the core component of vector sensor. The working principle of airborne particle velocity sensor in ways of numerical analysis, and effects as optimal sensitivity and low-pass filter on the frequency response due to the size of sensor head bridge structure, heat diffusion and specific heat capacities of materials are systematically presented here. The sensor head bridge structure is made by a serial of experimental MEMS process, the O℃ resistance value R₀ and the thermal coefficient of resistance θ of Pt are tested then, and finally the frequency response and the figure-of-eight directivity of the sensor are obtained. As a result, this airborne particle velocity sensor is of good acousticM characteristics.