The invention provides a dust removing system and a dust removing method. A tabletop supporting a to-be-cleaned part is arranged in the vertical direction, the to-be-cleaned part is also vertically arranged, and secondary pollution caused by the fact that particles raised by gas injected to the surface of the to-be-cleaned part through a nozzle fall to the surface of the to-be-cleaned part again through a nozzle is avoided; and a particle detection device detects particle information on the to-be-cleaned part, a control unit of a dust removing device is used for controlling the nozzle to move to the opposite position of the particles according to the particle information, the nozzle can be aligned with the particles to inject gas, and therefore the particles can be effectively removed in a targeted manner, and the situation that the particles fall back to the to-be-cleaned part, and secondary pollution is caused is avoided.