A hydraulic cylinder assembly, comprising: a cylinder; a cylinder liner disposed within the cylinder and being moveable between a first position and a second position; a piston disposed within the cylinder liner and being moveable between a third position and a fourth position; and a piston rod connected with at least one of two end faces of the piston and defining a free end extended out of the cylinder, wherein the cylinder defines a first oil inlet, a second oil inlet, a first oil outlet therein; wherein the cylinder liner defines a first oil port and a second oil port therein; wherein a first oil chamber and a second oil chamber are defined by the cylinder, the cylinder liner and the piston and located at two sides of the piston respectively, the first oil chamber is normally communicated with the first oil port, and the second oil chamber is normally communicated with the second oil port, characterized in that: the cylinder defines a second oil outlet therein, wherein when the cylinder liner is located at the first position, a communication between the first oil inlet and the first oil port is formed, a communication between the second oil inlet and the second oil port is interrupted, a communication between the first oil chamber and the first oil outlet is interrupted, and a communication between the second oil chamber and the second oil outlet is formed, wherein when the cylinder liner is located at the second position, the communication between the first oil inlet and the first oil port is interrupted, the communication between the second oil inlet and the second oil port is formed, the communication between the first oil chamber and the first oil outlet is formed, and the communication between the second oil chamber and the second oil outlet (153,154) is interrupted. a cylinder; a cylinder liner disposed within the cylinder and being moveable between a first position and a second position; a piston disposed within the cylinder liner and being moveable between a third position and a fourth position; and a piston rod connected with at least one of two end faces of the piston and defining a free end extended out of the cylinder, wherein the cylinder defines a first oil inlet, a second oil inlet, a first oil outlet therein; wherein the cylinder liner defines a first oil port and a second oil port therein; wherein a first oil chamber and a second oil chamber are defined by the cylinder, the cylinder liner and the piston and located at two sides of the piston respectively, the first oil chamber is normally communicated with the first oil port, and the second oil chamber is normally communicated with the second oil port, characterized in that: the cylinder defines a second oil outlet therein, wherein when the cylinder liner is located at the first position, a communication between the first oil inlet and the first oil port is formed, a communication between the second oil inlet and the second oil port is interrupted, a communication between the first oil chamber and the first oil outlet is interrupted, and a communication between the second oil chamber and the second oil outlet is formed, wherein when the cylinder liner is located at the second position, the communication between the first oil inlet and the first oil port is interrupted, the communication between the second oil inlet and the second oil port is formed, the communication between the first oil chamber and the first oil outlet is formed, and the communication between the second oil chamber and the second oil outlet (153,154) is interrupted. the cylinder defines a second oil outlet therein, wherein when the cylinder liner is located at the first position, a communication between the first oil inlet and the first oil port is formed, a communication between the second oil inlet and the second oil port is interrupted, a communication between the first oil chamber and the first oil outlet is interrupted, and a communication between the second oil chamber and the second oil outlet is formed, wherein when the cylinder liner is located at the second position, the communication between the first oil inlet and the first oil port is interrupted, the communication between the second oil inlet and the second oil port is formed, the communication between the first oil chamber and the first oil outlet is formed, and the communication between the second oil chamber and the second oil outlet (153,154) is interrupted.