The invention discloses a brine deicing device of railway tunnels, wherein the brine is calcium chloride brine below a saturation level, and the brine deicing device consists of a brine tank, a connecting pipe, a delivery pump, a pressure regulating valve, a return pipe, a delivery pipe, a liquid outlet pipe and a fixing clip. The brine tank is arranged over one side of a tunnel opening, the delivery pump is arranged near the brine tank, the connecting pipe is provided between the brine tank and the delivery pump, the liquid outlet of the delivery pump is connected with the delivery pipe, the pressure regulating valve is connected on the delivery pipe, the return pipe is connected on the pressure regulating valve, the liquid outlet pipe is connected on the delivery pipe, and the liquid outlet pipe is installed on the wall of the tunnel by the fixing clip. According to the brine deicing device of the invention, the effluent water droplets are salinized by the brine in the liquid outlet pipe to lose the freezing function and flow onto the ground along the outer wall of the liquid outlet pipe.