The valve-regulated proportional fertilization pump has many advantages, including low price, fertilization ratio adjustment of three-way valve, simpler structure and fewer parts; however, it also faces some shortcomings that need addressing, such as structural defects and small application range. In this paper, in order to reduce the parts of the fertilization pump and improve its application range, an improved design of the fertilizer suction components was proposed. Then the performance comparison test between improved fertilization pump and the original product was carried out. The test results show that the improved fertilization pump has a larger pressure difference application range than the original product. The uniformity of fertilizer suction per cycle can be maintained within the range of 0.04 MPa-0.40 MPa, and the largest fertilization proportion can be stably maintained at 0.62% within the range of 0.10 MPa-0.40 MPa. It shows that the improved design of the fertilizer suction component is feasible and highly stable, which can expand the application scope of the fertilization pump. The research results can provide some guidance for the overall design and optimization of proportional fertilization pumps.