Abstract: As continuous cropping of potatoes produces many hazards, it is important to study the effects of intercropping with legumes on the activities of key enzymes of carbon and nitrogen metabolism in potato leaves and crop yields and to select suitable potato cultivation modes to improve the efficiency of agricultural production, protect the ecological environment, and promote the sustainable development of agriculture. We measured the activities of key enzymes relative to carbon and nitrogen metabolism of potato leaf, and crops yields. The results showed that intercropping with legumes could significantly increase the activities of carbon and nitrogen metabolism-related enzymes in potato leaves, increase the yield of the population, and improve the land utilization rate; intercropping between potato and soybean (PS) performed the best. Correlation analysis showed that all enzymes activities of carbon and nitrogen metabolism were positively correlated with yield and that there was a significant positive correlation between the key enzymes of carbon metabolism (sucrose synthase and sucrose phosphate synthase) and the key enzymes of nitrogen metabolism (glutamine synthase and nitrate reductase). Principal component analysis showed that soluble sugars, sucrose phosphate synthetase, glutamine synthetase, and nitrate reductase played dominant roles in improving potato yield during intercropping with legumes. The land equivalent ratios of intercropping between potatoes and legumes were all greater than 1, and the average two-year land equivalent ratio of intercropping between potato and soybean (PS) was 1.20, showing significant intercropping advantages. In conclusion, there is a significant positive correlation between potato leaf carbon and nitrogen metabolism enzymes, which promotes yield formation, and intercropping with beans can significantly enhance potato leaf carbon and nitrogen metabolism enzyme activity, thus improving group yield. In the semi-arid region of southern Ningxia, to overcome the obstacles of potato succession, promote sustainable agricultural development, and enhance economic benefits, we can promote intercropping modes of potatoes and beans, with intercropping of potato and soybean (PS) being the most suitable.