The invention discloses an active temporary speed-limit tag and a signal processing method thereof, which is used for solving the technical problem of the traveling safety of a train and the low energy consumption of the active temporary speed-limit tag. The active temporary speed-limit tag comprises a microprogrammed control unit (MCU), a radio frequency transceiver, a clock module, a matching network, a microstrip antenna, a sensor awakening circuit, a sound sensor, a vibration sensor, an energy detection module, a high-energy charging battery, a battery charging circuit and a battery protective circuit. The signal processing method comprises the following five state circulating processing courses: a deactivating state, a sleeping state, a data reading state, a data transmitting state and a receiving waiting state. Moreover, the invention also provides a sleeping activating algorithm (WS) for the active temporary speed limit and a scheme for installing the active temporary speed-limit tag on a railway. Compared with the existing temporary speed limit technique of the train, the invention has the advantage that the potential safety hazards of the train such as reading mistake or reading leakage and the like caused by anthropogenic factors are solved by utilizing an automatic identification technique.