The invention discloses a train pipe low-pressure protection system and method applicable to a locomotive braking system, belonging to the field of locomotive braking systems, and aiming at solving the problems that precontrol pressure fluctuation is large, total wind consumption is high and energy is wasted when the traditional pressure limiting method is adopted and braking force of the locomotive is easy to attenuate. The train pipe low-voltage protection system disclosed by the invention comprises a pressure regulating valve, a two-position three-way pneumatic valve, an or gate shuttle valve, a fireless feedback safety valve, an operating valve and a volume chamber, wherein pressure of the volume chamber is only related to commonly pressure reduction of a train pipe, a channel used for controlling the operating valve is added by virtue of the pressure regulating valve, the two-position three-way pneumatic valve and the or gate shuttle valve, low pressure protection on the train pipe is realized by virtue of the added control channel, and control function of the braking system is improved. By adopting the train pipe low-pressure protection system and method disclosed by the invention, low pressure protection on the train pipe is realized, the problem that leakage is caused in a DK-1 braking system such as a distributing valve, a safety valve and the like is solved, and life cycle operating cost of a locomotive is saved.