The invention discloses a load test board with a sail stress simulation function. Mechanical hardware of the load test board includes a base, an oil tank, a motor, a low-speed large-torque motor, a pinion, a main gear, a gear shaft, a bearing and bearing seat set, a reducer, a coupler, a magnetic powder brake, an encoder and a torque sensor. According to the arrangement, the rotating angle of main gear simulates that of the sail; the magnetic powder brake is used with the reducer to simulate resistance applied onto ship during sailing. A hydraulic system of the load test board comprises the oil tank, the motor, a gear pump, a speed-regulating reversing valve, the motor, a one-way valve, a relief valve, a pressure sensor, a flow sensor and the main gear. The main gear is used for driving a sail rotation simulating mechanism. The load test board has the advantages that under varied wind field conditions, the stress applied onto the sail can be simulated in the real-time manner, structure is simple, operation is reliable, functions are complete, stability is high, and response speed is high.