Abstract: Use of Beidou navigation technology to achieve automatic, intelligent, and precise driving of agricultural machinery is a key direction for development of modern agricultural informatization in China．Based on Beidou navigation technology, research status of automatic driving system of agricultural machinery at home and abroad was expounded, positioning algorithm of Beidou navigation machinery was studied, and a new PVT algorithm was put forward．Hardware of the system was designed using this algorithm, and experimental simulation car testing was conducted．Results showed that under certain conditions of site and weather, positioning accuracy of this scheme was relatively ideal．