The operational principle and technical characteristics of CY-400A combined salt mining machine are introduced.By researching on transfer functions of each part of the salt mining machine,a cascade control scheme for the self-leveling control of the salt-picking head has been proposed,and an automatic self-leveling system has been designed.The industrial tests showed that the control scheme is of good performance,can realize the automatic level adjusting of the salt-picking head by automatically regulating the flow and flowing direction of oil in its swing cylinders to ensure the salt-picking head always work in horizontal status and is not influenced by the lateral slope of the road surface on which the pedrails drive.