Abstract: The superconducting nanowire cryotron is composed of superconducting nanowires with characteristic sizes of several nm thick and 100 nm wide as the basic circuit cell. Utilizing the geometric design and localized electrothermal dynamics to switch a superconducting nanowire to normal state, such devices can work for digital logic, pulse amplification, current measurement, memory and so on. This paper introduces three kinds of superconducting nanowire cryotron devices, and summarizes the research and development progress of this field in recent years. Finally, from the perspective of applications, some challenges faced by superconducting nanowire cryotrons are briefly discussed, which provides suggestions for the following development.