Abstract: Aiming at the problem that the solid-phase material concentration detection in the spiral feeding pipeline is greatly affected by the solid-phase distribution,based on the capacitance detection principle,a spiral surface plate capacitance sensor was designed. The finite element simulation method was used to establish a three-dimensional finite element model of the capacitance sensor,and the sensitivity distribution characteristic of the capacitance sensor was simulated and analyzed.The influence of structural parameters such as source/detection plate angle,plate axial length,shield radius and protection plate angle on the indexes of the field of the capacitance sensor was analyzed. Using the single factor rotation method,the ideal level range of each factor was obtained. In order to reduce the uniformity error,the orthogonal experiment and variance analysis method were selected to obtain the priority of each factor and the optimal combination of them,and the sensitivity field uniformity error parameter is 5.06%. The uniformity verification test of detection field was designed,and the sensor was built. The measured sensitivity field uniformity error parameter is 5.43%,which significantly improves the soft field effect of the sensor detection field,reduces the influence of the solid-phase distribution on the detection of the solid-phase concentration,and meets the needs of practical applications.