The electrification and intelligent transformation of harvester to make it have independent operation ability is an important embodiment of the development trend of agricultural automation and intelligence. Based on a full feed combine provided by relative company, this paper makes an electric transformation for its reaping and threshing part, including mechanical design, electric circuit construction, brushless DC(Direct Current) motor installation and test. Based on the finite automatic state mechanism, the control system of the electric operation part is built. Its sequential start and stop functions, reel speed following function and blockage detection and discharge function are tested in no-load experiment and farmland harvesting experiment. Through the continuous wheat harvesting test for 30 minutes, the power characteristics when harvesting wheat are measured, and the stability of its work is verified.