Abstract: In order to implement variable-rate technology in precision agriculture, it is essential to monitor and guide field vehicles in real time. In this paper, according to the actual conditions and the characteristics of dryland farming in China, a real time monitoring and management system based on GPS and GIS was developed using MapInfo Company's MapX4.5 ActiveX Control with Visual Basic 6.0. Common electronic map functions and various GIS tool modules were designed, including serial interface communication, map edition and network communication, a total of 17 modules. Control technology was used to design the serial interface and network to realize data transmitting and saving. Using dryland farm equipment as an example, a dynamic database and a query system for farm machinery were established. With the electronic map editing and real time monitoring, the system can determine and display the equipment location in the field, and can also perform data processing and management. Results from PC-PC testing show that the system has powerful functionality, good expandability and high practicability, and succeeds in combining dynamic monitoring with static analysis. This system provides a platform for further research on variable-rate application of intelligent agricultural equipment.