The main purpose of this thesis is to develop a swing device which can be used to a power spreader mounted on a motorcycle, in order to prevent and control the damage of red imported fire ants effectively. The swing device can replace the spraying gun handling of operators in spraying operation to save labor and increase spread efficiency. At the beginning of design, a CAD software called AutoCAD is used to draw and analyze the swing mechanism. After the simulation of trajectories of motion and limits of position, we can obtain an optimum size and angle for this swing mechanism. Then, a prototype of swing mechanism is designed by another CAD software called SolidWorks. Than a swing mechanism was developed according to the design. To prevent the red imported fire ants, baits must be spread at suitable time, on right place, and with proper quantity. The developed motorcycle-mounted power spreader can adjust its positions of throttle, openings of output volume and velocities of vehicle to obtain the optimum results of spreading amount per hectare. The spreading width of a motorcycle-mounted power spreader is between 3 and 8 meter according to different positions of engine throttles. The results showed that the required spreading amount 2 kg/hectare to prevention of the red imported fire ant can be achieved if output volumes are in position No.1 and No.2. If the output volume is in position No.1, the motorcycle’s optimum velocity is 10 km/h and if the output volume is in position No.2, the optimum velocity will be 30 km/h.