The invention provides a vehicle height adjustment control method and device for a multi-axle heavy vehicle. The method comprises the following steps: communicating same sides of two front axles of a multi-axle heavy vehicle, communicating same sides of four rear axles, and dividing a whole vehicle into a left front equivalent support point, a right front equivalent support point, a left rear equivalent support point and a right rear equivalent support point; in a single point height adjustment mode state, controlling electromagnetic switch valves and proportional flow valves in different loops of a hydraulic system so as to control single ascending and descending of a left front part, a right front part, a left rear part and a right rear part; in a road running mode state, presetting a first target value of an adjustment height, and controlling the electromagnetic switch valves and proportional flow valves in different loops so as to control the left front part, the right front part, the left rear part and the right rear part to meet the first target value; and in a rail way transportation mode state, presetting a second target value of the adjustment height, and controlling the electromagnetic switch valves and proportional flow valves in different loops so as to control the left front part, the right front part, the left rear part and the right rear part to meet the second target value.