At present, there are few theoretical and analytical models of tapered fertilization disc in China, which cannot reach the ideal width, and the uniformity of throwing fertilization is poor. A model of the movement of fertilizer particles on a conical fertilizing disk and in air was established. Considering the influence of rotation of fertilizer particles in the whole movement process, the absolute velocity of fertilizer granules moving to the edge of the vane was analyzed, and the three-dimensional coordinate system which was thrown into the air from the edge of the vane was established. The law of movement of fertilizer particles to the air was analyzed. The main factors influencing the movement of fertilizer particles were obtained, and then the main influential factors that affected the throwing distance and throwing uniformity were obtained. These influencing factors involved the movement parameters and structural parameters, including vane length, vane inclination and disc speed. After determining these influencing factors, coefficient of variation was elected as test index, a static bench experiment was carried out by the orthogonal experiment plan, which was conducted in the Engineering College of Northeast Agricultural University in early October 2017. Static experiment referred to International Organization for Standardization (ISO) 5690 and American Society of Agricultural Engineers (ASAE) S341.2. Static test used two-dimensional collection matrix method. The collection matrix area consisted of 253 boxes, each collecting box had external dimensions of 20cm×20cm×10cm and its thickness was 4mm. The experimental results were obtained in data processing, the results showed that the influencing factors were all significant. When the length of the blade was 145mm, the inclination angle of the vane was 0°and the rotating speed of the disc was 1200r/min, the horizontal coefficient of variation of throwing was 5.80%, which met the requirements of throwing fertilizers. The research can improve the fertilization efficiency of potato and provide a theoretical reference for the design and optimization of potato manure spreader.