Variable Rate Technology (VRT) is the goal of precision agriculture. In ordet to realize VRT, it is necessary to measure yield accurately and build yield map in real time. A grain yield monitoring system based on IPC (Industrial Personal Computer) was integrated and developed to fit for China actual conditions and combines. The system consisted of a hardware part and a software part. The hardware part included IPC, CAN-bus module, GPS receiver, GPRS transmission module, and yield monitoring sensors. The CAN-bus module, GPS receiver and GPRS transmission module were integrated with IPC. The yield monitoring sensors included a dual-plate differential flow transducer, a grain temperature sensor, a grain humidity sensor, a ground speed transducer, a grain elevator speed sensor and a header height sensor, which were connected to the CAN-bus module. The software part included five main modules, device settings module, data receiving module, data delivering module, data processing module, and data analyzing module. Firstly, the system used CAN-bus technology to construct a sensors network so that the signals of the grain flow, grain temperature and humidity, ground speed, elevator speed and the header height could be sent to the CAN-bus via CAN converting module. Then, the IPC collected data packets on the CAN-bus and recorded and displayed the yield data after analyzing and calculating through yield models. At the same time, IPC collected geographic information from GPS receiver and stored it with the yield data from CAN-bus on this location together as one record. Finally, the system uploaded the collected data to the host server in real-time or packaged it via GPRS. The experiments showed satisfactory results.