Abstract: In order to meet the combine header adjustment requirements of multi-crop combine harvester when harvesting different crops with different cutting height, the profiling mechanism which installed on both sides of the combine header is developed.The method of cooperative work of contact and non-contact sensors is used to detect the combine header height, and the average value of the detected header height is compared with the set value, then the combine header height is adjusted by fuzzy controller.The simulation and field test of automatic combine header height control of 4 LZ-5 B multi-crop combine harvester are carried out to verify the feasibility of the control algorithm.The results show that the automatic header height control system can operate stably when harvesting rape, rice and millet, and the control error is no more than 15 mm, which can meet the harvest requirements of different crops.