The invention discloses a control method for heightening a suspension of a special vehicle chassis. The control method comprises the following steps that step 1, a current operating mode of a specialvehicle is read, and a target value of suspension height corresponding to the current operating mode is invoked; step 2, the actual value of the suspension height fed back by a height sensor is obtained; step 3, the height tolerance is calculated based on the actual value of the suspension height and the target value of the suspension height, and a proportional valve is controlled according to theheight tolerance to output according to target flow; step 4, the action of a solenoid valve is controlled based on the output target flow; and step 5, the suspension to be adjusted is adjusted to thetarget height. The control method for heightening the suspension of the special vehicle chassis can meet the requirements of vehicle height for the special vehicle under different driving conditionsand different transportation conditions, so as to effectively improve the smoothness and operational stability of the special vehicle in the driving process and enabling the special vehicle to pass easily on various road surfaces.