The invention relates to an air spring provided with a locking device. The air spring can be lengthened without changing the force of the air spring. The air spring comprises a spring body, a locking shell, a rotary hinge pin, a piston rod, another piston rod, an air cavity partition device, a bearing end and a cylinder barrel. The cylinder barrel is divided into two air cavities. One piston rod is arranged in one air cavity, and the other piston rod is arranged in the other air cavity. The piston rods are connected with the bearing end. The bearing end and the locking shell are connected into a whole in a relatively rotating mode through the rotary hinge pin. The rotary hinge pin, the locking shell and the bearing end form a lever structure. One end of the spring is fixedly connected to the bearing end. One end of the locking shell is pressed onto the other end of the spring. A clamping part is arranged at the other end of the locking shell and can be clamped to the end of the cylinder barrel. The air spring is improved, one air cavity is divided into two cavities, one piston rod is replaced by two piston rods, and both ends of the air spring can be stretched and compressed; and the structure is simple and reliable, and the manufacturability is good.