Agricultural spraying unmanned aerial vehicles (UAV) become a new hot spot in intelligent agricultural machinery field. It has a lot advantages over traditional spraying method like manual spraying and machine spraying. There is an urge need of UAV spraying technology. Meanwhile, since UAV onboard spraying takes a lot of time to prepare and is highly risky because for now there was a lack of customized flight controller for agriculture spraying. The development of an UAV aerial spraying simulation system was described. This system was developed for aerial spraying theory and methods test so as to shorten experiment cycle and motivate new spraying methods to be optimized. The system was designed and developed as a high precision, highly automated unmanned aerial vehicle (UAV) simulation platform to perform UAV indoor test. The system mechanical precision was maximum 2mm error for horizontal, maximum error 1mm for vertical, maximum load weight 50kg. MFC-based upper machine software was designed and it was communicated with the main control board to realize the horizontal and vertical directions movement. CAN bus was used for communication between main control board and the far end spraying unit controller. The far end spraying controller controlled spray flow control and rotor speed. This system can effectively reduce the spraying test vehicle costs, reduce the risk, and promote the UAV spraying technology development and testing. The system can be expanded to the agricultural plant protection spray test area in many places.