The invention relates to a load simulation mechanism of a circuit breaker operating mechanism and a load simulation test device. The load simulation mechanism of a circuit breaker operating mechanism comprises a buffer cylinder and a piston which is arranged in the buffer cylinder. The piston is provided with an operating lever which is in transmission connection with the operating mechanism and can drive the piston to move. A damping channel which is communicated with cavities on both sides of the piston is arranged in the piston, the buffer cylinder or at least one place between the piston and the buffer cylinder. When the piston moves toward a rod cavity, gas in the rod cavity is compressed, and gas in the rod cavity applies force on the piston to realize buffering when the gas comes into a rod-free cavity through the damping channel. When the piston moves toward the rod-free cavity, the compressed gas in the rod-free cavity comes into the rod cavity through the damping channel to apply force on the piston. According to the circuit breaker simulation test, the gas is used as a load; actual circuit breaker conditions can be realistically and effectively simulated; and the credibility of a test result is high.