Abstract: Agricultural and rural modernization is an essential part of the socialism modernization in China. However, unbalanced development of agricultural and rural modernization among different regions still exists. Therefore, it is necessary to promote the modernization of agriculture and rural areas according to local conditions. A scientific evaluation of the development levels of agricultural and rural modernization in less developed areas is an important prerequisite for precise policy implementation, which is conducive to a healthy and rapid development of agriculture and rural areas. Taking Yunnan Province as an example, this paper evaluated the development level of agricultural and rural modernization in Yunnan Province from 2006 to 2020 based on a comprehensive evaluation method, the coupled coordination degree model and the obstacle degree model and analyzed the coupled coordination degree of internal subsystems and the constraint factors. Results show that the development level of agricultural and rural modernization in Yunnan Province is on a continuous rise and is in the initial stage. The two subsystems of agricultural and rural modernization in Yunnan Province show high coupling and low coordination level. The percentage of income from rural tourism, the number of village health room personnel per 1, 000 people, the number of agricultural science and technology personnel per 1, 000 people, the percentage of output value of agriculture, forestry, animal husbandry and fishery service industry, the percentage of adopters in elderly service institutions, and the amount of pesticide and chemical fertilizer application become the main factors impeding the modernization process of Yunnan's agriculture and rural areas. Therefore, to promote modernization of Yunnan's agriculture and rural areas, this paper suggests: 1) to focus on comprehensive productivity enhancement and village construction; 2) to continuously develop modern agriculture with highland characteristics and promote the integration of agriculture and tourism; 3) to intensively improve the construction of village health offices and elderly service facilities; 4) to strengthen the introduction and training of agricultural science and technology personnel; 5) to accelerate the improvement of agricultural socialization services; and 6) to continuously carry out the action of reducing the amount of pesticides and chemical fertilizers and increasing the application of organic fertilizers to ensure a stable development of ecological agriculture.