The invention discloses a large-stroke suspension system for a multi-axle heavy vehicle. The large-stroke suspension system is composed of suspension devices on the two sides of each vehicle axle. Each suspension device comprises an upper cross arm assembly, a lower cross arm assembly and hydro-pneumatic springs. The vehicle axles are divided into a front vehicle axle set composed of m vehicle axle bodies and a rear vehicle axle set composed of n vehicle axle bodies. The hydro-pneumatic springs on the left side of the front vehicle axle set are connected with first energy accumulators correspondingly and enable the first energy accumulators to communicate with one another. The hydro-pneumatic springs on the right side of the front vehicle axle set are connected with second energy accumulators correspondingly and enable the second energy accumulators to communicate with one another. The hydro-pneumatic springs on the left side of the rear vehicle axle set are connected with third energy accumulators correspondingly and enable the third energy accumulators to communicate with one another. The hydro-pneumatic springs on the right side of the front vehicle axle set are connected with fourth energy accumulators correspondingly and enable the fourth energy accumulators to communicate with one another. The large-stroke suspension system for the multi-axle heavy vehicle has the advantages of being simple in structure, easy to implement and wide in application range; and by adoption of the large-stroke suspension system for the multi-axle heavy vehicle, driving smoothness, handling stability and passing ability of the vehicle can be effectively improved.