In order to obtain the optimal irrigation and nitrogen topdressing scheme，the comprehensive effects of irrigation and nitrogen topdressing on potato yield，irrigation water and fertilizer utilization efficiency and soil enzyme activity were investigated.In the field experiment，three irrigation levels of W1(900 m3/hm²)，W2(1350 m3/hm²) and W3(1800 m3/hm²) and three nitrogen fertilizer application ratio of base to topdressing of F1(N2∶1)，F2(N1∶1) and F3(N1∶2) were set up，with a total of nine treatments.The comprehensive growth evaluation system of potato in Ningxia central arid region was established by entropy weight TOPSIS method，and the interaction response mathematical model of potato irrigation levels and different nitrogen application ratios of base to topdressing was established with the goal of high yield，water saving and fertilizer saving.The results showed that the yield per plant，yield，iWUE (irrigation water use efficiency)，PFP (fertilizer partial productivity)，soil alkaline phosphatase and soil sucrase were significantly affected by irrigation amount and application ratios of base to topdressing.The comprehensive evaluation system of potato was established by using TOPSIS method，and the optimal comprehensive response score was 0.1761，which was A7 treatment. The interaction response model of potato comprehensive growth to irrigation level and nitrogen application ratios of base to topdressing showed that the single factor of irrigation level or nitrogen application ratios had an open downward quadratic parabola on potato comprehensive growth，and the interaction effect of them was significant.When the fertilization code was -0.7723 (base fertilizer∶topdressing =1.6553∶1) and the irrigation code was 0.6553 (1697.535 m3/hm²)，the comprehensive score was the highest.The comprehensive score of 0.16 was used to divide the closed area，and the optimal irrigation interval and nitrogen application ratio of base to topdressing in potato production were 1∶1～2.3∶1 and 1440～1935 m3/hm²，respectively.This interval was the most conducive to realize the optimal potato synergistic effect.