An inert gas gear shifting speed regulating system for an underground coal mine fracturing pump set is provided with a gas storing tank which supplies inertia pressure gas. The gas storing tank is connected with anti-explosion electromagnetic valves through gas circuits, and the anti-explosion electromagnetic valves are connected with a speed changer upshift connector and a speed changer downshift connector through quick exhausting valves. According to the inert gas gear shifting speed regulating system for the underground coal mine fracturing pump set, two exhaust ports of the whole system are connected with a speed changing box upshift and a speed changing box downshift respectively according to ports of a speed changing box mechanical gear shifting mechanism, an inert gas (nitrogen) bottle is taken as a gas source by the system, nitrogen is conveyed to the gas storing tank, control over the gas circuit is completed through the control motion to the anti-explosion electromagnetic valves, and therefore the motion to the speed changing box upshift and the motion to the speed changing box downshift are completed, and remote gear shifting speed regulation of the underground coal mine fracturing pump set is achieved.