Abstract: At present, most domestic breeding companies in China still adopt the artificial check way to finish the measurement of production which leads to labour-intensive and low working efficiency and makes the quality of test data far from the data quality of yield monitor system adopted by developed countries. To solve this problem, a kind of harvester yield monitoring system was designed based on the plot breeding which mainly includes host computer part and slave computer part. The single chip of MSP430 from TI company was applied on slave computer, which can acquire the information such as the productivity of harvester, grain moisture content, environmental temperature, environmental humidity and the GPS with the measurement unit such as grain moisture sensor, gravity sensor, temperature sensor, humidity sensor, and the GPS module. The host computer took the embedded touch panel as the human-computer interface which can run MCGS software. The host computer and slave computer communicated for each other by the serial port of RS-232 and the protocol of ModBus. This system can automatically make accurate corresponding relations between block number and related production data, and had the ability of the data management such as the mass data import and export with usb flash disk. The scheme of the harvester yield monitoring system are proved correct and feasible by use of virtue experiment, this system obviously improves the breeding test production efficiency and the accuracy of data.