A thermal expansion valve includes a power head and a valve body. The power head and the valve body are fixedly arranged. The power head includes a power head cover, a power head seat, and a membrane. The membrane includes a membrane recess and a corrugated portion. The membrane recess is located at the center position of the membrane. The corrugated portion is located at the peripheral position of the membrane recess. The membrane recess is recessed away from the power head cover. The valve body comprises a top portion. The top portion is provided with an opening. At least a part of the power head is extended into the opening. With an axial direction of the valve body as a projection direction, a projection of the power head towards the top portion falls on the top portion.