To strengthen the country, agriculture must be first strengthened, and only by strengthening agriculture can the country be strong. The report of the 20th National Congress of the Communist Party of China takes “basically realizing agricultural modernization” as one of the overall development goals of China in 2035. Comprehensively promoting rural revitalization and accelerating the construction of agricultural power, are the strategic deployment of the Party Central Committee in order to comprehensively build a modern socialist power. Since the reform and opening up, Nanjing’s agriculture has developed rapidly and its agricultural competitiveness has improved rapidly. However, compared with the developed agricultural areas in China, the agricultural competitiveness is not strong. The number of agricultural employees in Nanjing is only 210 000, with an average annual decrease of 20 000. The per capita cultivated land is 0.025 hectares, which is only 25% of the national average. Brand awareness is not enough, and it suffers from fierce competition in the industry. Based on the diamond model analysis framework, this paper analyzes Nanjing’s agricultural competitiveness from five aspects: production factors, demand conditions, related supporting industries, enterprise strategic structure and industry competition, government, and opportunities. This paper puts forward five strategies to improve the competitiveness of modern agriculture, including talents, science and technology, capital, land, and enterprise competitiveness, to give full play to the advantages of human resources in Nanjing, continuously optimize the environment of human resources, and do a good job in the internal allocation and external introduction of agricultural talents. Relying on innovation carriers such as agricultural high zone and agricultural innovation Park, accelerate the integrated innovation of key technologies in leading agricultural industries such as efficient facility vegetables, economic forest fruits, and agricultural product processing, and promote the“going out” and “bringing in” of Nanjing agriculture; establish a diversified agricultural investment system guided by financial support for agriculture to provide financial support for the development of modern agriculture and comprehensively enhance the competitiveness of agricultural enterprises. Through the promotion of agricultural competitiveness, the agricultural modernization of Nanjing will be accelerated, so as to provide strength to help China build an agricultural power.