The invention discloses an automatic speed changing type airport pavement crack sealing system and a use method thereof. The system comprises a gas cylinder, a triple valve, a main pipeline, a first branch pipeline, a second branch pipeline, a pneumatic vibrator, a solid particle delivery pipeline, a controller, a powder storage and gas-solid mixing device, and a pavement crack sealing cover, wherein a gas output from the gas cylinder enters a Venturi mixer; then solid particles enters the Venturi mixer through a solid particle storage chamber; the gas and the solid particles are mixed in the Venturi mixer to form a gas-solid mixture which is delivered to the pavement crack sealing cover to seal airport pavement cracks; with the sealing, the system disclosed by the invention can automatically change speed and adjust the gas-solid mixing ratio, so as to ensure that the effect of sealing the cracks is good and greatly prolongs the service life of an airport pavement; the system has broad practicability; moreover, the vibration of the pneumatic vibrator can prevent the solid particles from being adhered to an inner wall of the solid particle storage chamber, thereby guaranteeing continuity of delivery of solid particles.