A suspension control system which provides a vehicle height signal representative of a vehicle height, a vehicle height data signal responsive to said vehicle height signal, and a first determination signal representative of a suspension characteristic alteration if a difference between a maximum and minimum value of said vehicle height data signal within a predetermined suspension characteristic alteration determination time interval exceeds a first value thereof, and which alters said suspension characteristic in response to said first determination signal. A suspension system which has a similar operation as said suspension system except that it provides a second determination signal representative of suspension characteristic restoration instead of a first determination signal if a difference between a maximum and minimum value of said vehicle height data signal within a first time interval of restoring determination is less than a second reference value thereof for a predetermined number of consecutive times, and which alters vehicle height.