This study put forward a novel high precision digital curvilinear displacement sensor.The high frequency pulses were used to represent the magnitude of curvilinear displacement based on geometry analyse. The mechanical structure design of the sensor was completed. The working principle of curvilinear displacement sensor was analyzed in detail. The hardware and software design of the interface circuit of the sensor was completed and the performance of the sensor was analyzed. Compared with the traditional curvilinear displacement sensors, the sensor proposed in this paper has features of high precision, efficiency, explicit structure, low cost, wide measuring range, no need to adjust zero and it has general application value in industry field.