Abstract: Smallholder farmers are the main body of agricultural production in China, but there are big variations in the crop yields and efficiency of resource utilization among these farmers. To increase the yield and nutrient use efficiency of crops and ensure precise management of smallholders' plots, this research established a management system for wheat and maize that produces high yield and nitrogen use efficiency at the village level, based on GIS using C# language. The verification of system effects was carried out through the field comparative test on the farmland and a feasibility evaluation was conducted by investigating farmers. During the farmer survey, the farmers were classified into 3 categories, which included the test farmers in whose fields the comparative test was conducted, radiation farmers who often interacted with researchers, and ordinary farmers who were not influenced by researchers. The results showed that the management system, based on peasant household plots, created high yield and nitrogen use efficiency for each farmer in the village, through information queries, data analyses, management decision making, system management, and other functional modules. The results of 22 comparative experiments in two years showed that, compared with the farmers practice treatment (FP), the treatment with high yield and nitrogen use efficiency (DH), recommended by the system, increased the winter wheat yield and partial nitrogen fertilizer productivity (PFP_N) by 10.8% and 28.5%, respectively. The treatment system (DH) recommended during the maize season increased the yield and PFP_N by 10.3% and 16.9%, respectively. This indicated that, with technological support from the recommendation system, farmers could be increasing their yield and nitrogen use efficiency of the winter wheat and summer maize, simultaneously. The results of the farmers' investigation showed that smallholders had a high degree of recognition for the management system, making it feasible to use the system for technical recommendations. Farmers had a high recognition for the recommended technologies for winter wheat and summer maize, but the adoption rate varied greatly. In particular, the adoption rate of recommended wheat varieties was 94%, but the adoption rate of precision sowing technology for winter wheat was 29%. The adoption rate of densification technology and late harvest technology of summer maize was only 2% and 35%, respectively. The recognition and adoption rates of the test and radiation households, which were greatly influenced by the technical recommendations made by the scientific and technical personnel, were higher than that of the ordinary peasant households. This indicated that it was feasible to popularize the management system to peasant households. In conclusion, the management system of winter wheat and summer maize for high yield and nitrogen use efficiency incorporated the auxiliary decision-making of crop management technology for smallholder plots, and had a significant effect on increasing the yield and nutrient use efficiency, which provided the possibility of achieving high crop yield and nutrient efficiency in large areas.