A smart device for a tire capable of preventing leakage by means of a network comprises a wheel rim (1), an outer tire (2), inner tires (3), and anti-leakage valves (4). The anti-leakage valves comprise a first anti-leakage valve (5) and a second anti-leakage valve (6). When the outer tire loses a pressure, the first anti-leakage valve is closed by means of a first driving rod (24) and a first inner tire (7) supports the outer tire by means of a first outer supporting column (18) and a first inner supporting column (19). Meanwhile, a TPMS device transmits pressure loss data of the outer tire of a motor vehicle to a controller (96); the controller transmits, through the Internet, the pressure loss data to the motor vehicle and a satellite positioning device (99) of a motor vehicle following behind the motor vehicle. The controller of the motor vehicle and the controller of the motor vehicle following behind the motor vehicle cut off ignition circuits of engines thereof and control active braking devices thereof to brake, so as to reduce flat tire accidents and collisions between the motor vehicles.