As the new crown epidemic ravaged the world, China's grain production has been greatly impacted and challenged. Studying the current situation of grain production in Yunnan Province is of great guiding significance for its future grain production structure adjustment and optimization layout. In this study, the spatiotemporal changes in grain production in This paper mainly uses the logarithmic method to calculate the contribution rate of the influencing factors, the decomposition and calculation method of the contributing factors of the change of grain total output, the gravity shift model and the grain yield volatility coefficient to analyze the spatio-temporal changes of grain production in Yunnan Province. Through the analysis of data, the following results were obtained: (1) In the past 30 years, the grain planting area and yield in Yunnan Province have shown a significant upward trend. In particular, the total output growth rate has reached 97% and the increase in the single yield of each crop and adjustment of the planting structure are the main contributors to the increase in the total grain output of the province. The planting area of rice and wheat has decreased by 16% and 36%, respectively, over 30 years, and the total and single yields have not changed substantially. The growth rate of the planting area, total yield, and single yield of maize is most obvious. The changes in the total yield of potatoes during the study period were all caused by changes in planting area, with contribution rates of 85%, 78%, and 206%, respectively, in the three periods. (2) The grain planting area and output in Yunnan Province generally show the distribution law of more east and less west. The most abundant area is Qujing City and the least is the Diqing Tibetan Autonomous Prefecture. The center of gravity of grain production has a tendency to migrate to the northeast. Rice production is decreasing from southeast to northwest, and the high-value areas of wheat yield are gathered from all sides to the middle. Corn production is the fastest, and potato high-yield areas are mainly distributed in northeast Yunnan. (3) In the past 30 years, the per capita grain in Yunnan Province has increased by 111.56 kg/person, and the grain production capacity has improved and is currently of the self-sufficient type. However, the fluctuation coefficient of more than 70% of the years exceeds the national average, grain supply is relatively unstable, and contradiction between grain supply and demand remains prominent. It is concluded that the grain planting area and yield in Yunnan Province have gradually increased, the current situation of grain production is mainly self-sufficient, and the differences between the main grain crop-producing areas are quite large, and it is extremely important to pay attention to the optimization of the grain planting structure and promote the stable increase of grain production. At the same time, according to the analysis results, this study proposes that the main problems of grain production in Yunnan Province are (1) the decline in the amount of cultivated land; (2) the high number of medium and low yield fields; and (3) the phenomenon of "non-grainization" is more serious. In the face of the development status of grain production in Yunnan Province, relevant departments still need to pay attention to the quantity and quality of cultivated land, adjust the agricultural planting structure, and comprehensively improve grain production capacity in the future. It is necessary to (1) increase subsidy policies and adhere to the red line of cultivated land; (2) invest in relevant technologies to increase grain yields; and (3) coordinate the process of urbanization development and adjust the planting structure according to local conditions. This study investigated the spatiotemporal changes in major crop production in Yunnan Province over the past 30 years; obtained corresponding conclusions on timing changes, spatial distribution, and contributing factors; analyzed the current grain production security situation in Yunnan Province; summarized the main problems in its development process; and put forward targeted suggestions, so as to further develop a deeper understanding of the current situation of grain production in Yunnan Province to play a certain guiding and reference role in its future development and planning direction. [ABSTRACT FROM AUTHOR]