Abstract: To acquire grain yield distribution information and develop digital agriculture, a method for acquiring and analyzing yield data at harvesting time was studied. By Global Positioning System(GPS) and Geographical Information Systems(GIS), after coordinate transformation and other data processing, digital maps of the territories were obtained, and the combine track was displayed in the digital map dynamically. Through disposing the data of the yield-instrument sensors and GPS receivers, yield wave curve and a yield map of the sampling points can be generated and revealed according to the yield data together with its corresponding coordinates. Through the header height, real-time reaped area was calculated. During post treatment, spatial analyses were made to attain the yield distribution. Experiments show that the system can create a digital map rapidly, and display the combine track and the reaped area synchronously. The digitization of grain yield distribution can provide guidances for farming production scientifically.