The invention discloses an expansion valve which comprises a main valve body, wherein a valve cavity is formed inside the main valve body; a main inlet and a main outlet are formed in the valve cavity; a valve core is mounted inside the valve cavity; the valve core divides the valve cavity into an upper cavity and a lower cavity which are not communicated with each other; a spring for pushing the valve core to move downwards is arranged inside the upper cavity; a pressure release hole which is communicated with the main outlet is formed in the upper end of the valve core; a pilot valve is further arranged on the main valve body; the pilot valve comprises a pilot valve body and a pilot valve head; the pilot valve body is connected with the main valve body; a micro valve is mounted on the pilot valve head; the micro valve is used for controlling the main valve to open or close. The opening degree of the expansion valve can be randomly adjusted under the control of the micro valve, and the technical problem, in the prior art, that the opening degree of a valve mount of the expansion valve can be only adjusted according to the temperature sensed by a temperature wrap is solved. The embodiment of the invention is applied to the field of expansion valves.