Abstract: As continuous cropping of potato 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, to protect the ecological environment, and to promote the sustainable development of agriculture. We measured the carbon metabolism, nitrogen metabolism and crop yield of potato leaves. 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 utilisation rate, among which intercropping between potato and soya bean (PS) performed the best. Correlation analysis showed that all the indicators of carbon and nitrogen metabolism were positively correlated with yield, and 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 a dominant role in the improvement of potato yield in intercropping with legumes. The land equivalent ratios of intercropping between potato and legumes were all greater than 1, of which 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 effect between potato leaf carbon and nitrogen metabolism enzymes, and has a promoting effect on yield formation, intercropping with beans can significantly enhance potato leaf carbon and nitrogen metabolism enzyme activity, and thus improve the group yield. In the semi-arid region of southern Ningxia, in order to overcome the obstacles of potato succession, promote sustainable agricultural development and enhance economic benefits, we can promote intercropping modes of potato and beans, and intercropping of potato and soybean (PS) is the most suitable.