Abstract: A new constant cross-section double-acting piston pump applied in water and fertilizer integration machine was designed．Experiments were carried out on change of workflow of piston pump under different plunger stroke ratios（20%, 40%, 60%, 80% and 100%） and irrigation pipe pressures（0.04, 0.08, 0.12, 0.16 and 0.20 MPa））, and response relationship between stroke ratio, pipe pressure and workflow was analyzed．Quantitative study of improvement degree in efficiency of new piston pump over traditional piston pump, comparative analysis of fertilization efficiency, space occupation and weight with traditional piston pump was carried out．New piston pump could make irrigation of water and fertilizer integrated equipment more accurate by adjusting plunger stroke ratio．At full stroke, new piston pump saved 33% to 38% of average time to deliver the same flow compared with traditional piston pump; when pipe pressure rose from 0.04 MPa to 0.20 MPa, mechanical efficiency of new piston pump was increased by about 18% compared with traditional piston pump, and fertilization flow was increased by 32% to 45%; compared with traditional piston pump, new piston pump has reasonable structure, long service life of components, reduced occupation space by about 60%, reduced weight by about 62%, and reduced processing and transportation costs．From comprehensive analysis of mechanical efficiency, occupation space and weight, performance of new piston pump was better than traditional piston pump, which provided a certain reference for development of piston pump with high efficiency and lightweight．