Abstract: Under the superposition of risk factors at home and abroad, the phenomenon of "non-grain conversion" of cultivated land has aroused widespread concern. On the one hand, the threat of this phenomenon to food security cannot be underestimated; on the other hand, the moderate "non-grain conversion" of cultivated land, especially in the suburbs of metropolitan areas, has promoted the transformation and upgrading of agriculture and the multi-function of agriculture to a certain extent. With the beginning of "non-grain conversion" of cultivated land management, the lack of theoretical research and practical experience leads to many practical problems. To establish the theoretical foundation, this study defines the definition of "non-grain conversion" of cultivated land and develops a classification system. Furthermore, in empirical analysis, this study takes the water town functional area of Dongguan as the study area, adopts GIS spatial information analysis, multiple Logistic regression and other research methods, and obtains the following results: (1) Using the data of land use status and combining with survey and interview, the information of "non-grain conversion" of cultivated land is extracted. From 2010 to 2020, the ratio of "non-grain conversion" of cultivated land in the water town functional area of Dongguan has been stable at about 65%, among which, weakly damage accounts for 60% to 70%, progressive damage accounts for 2%, and serious damage accounts for 30% to 40%. The phenomenon of "non-grain conversion" occurred in five towns, among which, weak damage and progressive damage are the most distributed in Machong Town, and serious damage is the most distributed in Daojiao Town. From 2010 to 2015, the spatial distribution of non-grain cultivated land was roughly the same, and only a small number of land types changed. In 2020, the spatial distribution of cultivated land and non-grain cultivated land is different from that in 2010 and 2015. (2) Through constructing multiple Logistic regression model, it is found that among the natural factors, land area and quality grade of cultivated land had a positive impact on the "non-grain conversion" of cultivated land, and land regularity do not reflect statistical significance. Among the location factors, the distance from town center and rural residential area has positive influence on the "non-grain conversion" of cultivated land, while the distance from river, rural road and highway has negative influence on the "non-grain conversion" of cultivated land. Among the institutional factors, whether in permanent basic farmland has a positive impact on the "non-grain conversion" of cultivated land, and whether in high-standard farmland has a negative impact on the "non-grain conversion" of cultivated land. (3) It is proposed to adopt differentiated administrative control measures for different types of “non-grain conversion” of cultivated land, formulate the framework process of "monitoring-evaluation-warning-regulation", and carry out dynamic control on influencing factors. Therefore, the phenomenon of "non-grain conversion" of cultivated land in metropolitan suburbs should be under differentiated administrative control, and its influencing factors should be dynamically monitored, evaluated, forewarned and adjusted. The main contribution of this study is to focus on the problem of "non-food conversion" of cultivated land in metropolitan suburbs, explore its driving mechanism from a spatial perspective, and put forward a feasible differentiated governance path.