Abstract: The high temperature of the train axle could bring dangerous to the train operation, so it is very important to detect train axle temperature. This research was different from the design of other axle temperature detection. Mobile phone with Android platform and ARM11 development board was used to communicate with each other in order to implement real-time monitoring of temperature. Wi-Fi technology was used to receive real-time data from the development board, and the mobile phone was used to receive data in the socket communication process, while the ARM development board worked as the client to send temperature data, so that the mechanical engineer could observe the temperature values of each axle at any position of the train. After testing, the portable axle temperature alarming device for railway train could implement the function of axle temperature detection and transmit the data of axle temperature to the intelligent handheld terminal through wireless communication.