According to the latest Land Use Planning of Guangxi Zhuang Autonomous Region, Guangxi is divided into five regions, which are eastern Guangxi, western Guangxi, southern Guangxi, northern Guangxi, and central Guangxi. Regional variation characteristics of grain production are introduced from two aspects of the decline of grain sowing area and the increase of grain output. According to the data in Guangxi Statistical Yearbook, comparative advantages of regional grain production in Guangxi Zhuang Autonomous Region are analyzed by the method of Comprehensive Comparative Dominance index. Result shows that eastern Guangxi and northern Guangxi have the maximum comprehensive dominance indices with the minimum increasing amount of dominance indices. Their advantages in grain production are gradually diminished; and the grain production center is moving to central Guangxi and southern Guangxi. In order to solve the problems in grain production, Guangxi should make full use of the comparative advantage in agricultural production, carry out structural adjustment of agricultural production, and try to realize the rational distribution and specialization of agricultural production.