A thermostatic valve, comprising a housing in which an receiving cavity is provided, and a thermostatic actuating element mounted in the receiving cavity, wherein the receiving cavity is in communication with an outside through at least three connecting ports comprising a first connecting port, a second connecting port and a third connecting port; the thermostatic actuating element comprises a main body of the thermostatic actuating element in which a thermosensitive substance is provided, and the thermostatic actuating element is mounted in the receiving cavity of the housing via two elastic members; and an annular sealing collar which is fixedly mounted is provided in the receiving cavity, and the first connecting port and the second connecting port are located at two sides of the sealing collar, respectively; a first passage is formed in a case that the second connecting port, an inner hole of the sealing collar and the first connecting port are in communication with each other, and a second passage is formed in a case that the first connecting port and the third connecting port are in communication with each other; in a case that a fluid has a low temperature, the thermosensitive substance in the thermostatic actuating element contracts, the main body of the thermostatic actuating element is moved towards the sealing collar under the action of an elastic force of the respective elastic member, which enables a second engaging portion of the main body of the thermostatic actuating element or a second engaging portion fixedly provided on the main body of the thermostatic actuating element to abut against the sealing collar or cover the inner hole of the sealing collar, to block the first passage and open the second passage; and in a case that the fluid has a high temperature, the thermosensitive substance in the thermostatic actuating element expands, the main body of the thermostatic actuating elements moves towards the third connecting port, until a first engaging portion of the main body of the thermostatic actuating element or a first engaging portion fixedly provided on the main body of the thermostatic actuating element abuts against an end surface of a part of the housing where the third connecting port is located or covers the third connecting port, to block the second passage and open the first passage; wherein a first valve opening is provided in the housing at a position where the third connecting port is provided, and the first valve opening is a port communicating the third connecting port with a cavity where the main body of the thermostatic actuating element is provided; characterised in that the housing has an open end which is in communication with the receiving cavity, the open end of the housing is sealed by an cap which is fixedly and hermetically mounted; the thermostatic actuating element further comprises a piston which is slidably mounted at a first end of the main body of the thermostatic actuating element, and one end of the piston is located outside the main body of the thermostatic actuating element and passes through an annular hole of the sealing collar; and the two elastic members comprise a first elastic member and a second elastic member; the first elastic member is arranged at the cap or at a side adjacent to the cap, and the first elastic member has one end abutting against the cap, and another end abutting against or indirectly abutting against the piston at least during a moving process; the second elastic member is arranged at the third connecting port or a side adjacent to the third connecting port, and the second elastic member has one end abutting against an inner wall or a bottom wall of the receiving cavity of the housing, and another end abutting against the main body; an initial deformation force of the first elastic member is greater than or equal to a pressure applied to the second elastic member when the first engaging portion abuts against a part where the first valve opening is located.