The embodiment of the invention provides an emergency freezing system and method for a shield tail of a shield machine. The system comprises a liquid nitrogen tank, a liquid nitrogen storage box and afreezing pipe. The liquid nitrogen tank is arranged on a storage battery car matching the shield machine. The liquid nitrogen storage box is arranged on a trolley of the shield machine. The liquid nitrogen storage box is equipped with a liquid nitrogen inlet, a liquid nitrogen outlet, a nitrogen gas inlet and a nitrogen gas discharge opening. A liquid outlet of the liquid nitrogen tank communicates with the liquid nitrogen inlet of the liquid nitrogen storage box. The nitrogen gas discharge opening of the liquid nitrogen storage box is equipped with a discharge valve. The freezing pipe is arranged in a shield shell of the shell tail of the shield machine. An inlet end of the freezing pipe communicates with the liquid nitrogen outlet of the liquid nitrogen storage box. An outlet end of thefreezing pipe communicates with the liquid nitrogen inlet of the liquid nitrogen storage box. The system is reasonably designed, simple and easy to operate and is safe and efficient. Leakage water can be quickly blocked in order to reduce loss of particles in a surrounding stratum. Accordingly, construction safety is ensured.