The invention provides a residual heat removal system for a molten salt reactor buffer salt accident. The residual heat removal system for the molten salt reactor buffer salt accident system comprises a cooling tower, a main loop system and a salt filling and eliminating system, wherein a natural ventilation heat exchanger is arranged in the air cooling tower; a heater is arranged on the periphery of the natural ventilation heat exchanger; the main loop system is formed by connecting a molten salt pond, a heat tube section, the natural ventilation heat exchanger and a cooling tube section in sequence; a reactor core is arranged in the molten salt pond which is filled with molten salt; one tail ends of the heat tube section and the cooling tube section are respectively immersed in the molten salt in molten salt pond; the highest position of the heat tube section of the main loop system is connected with an expansion tank; the salt filling and eliminating system is connected with the molten salt pond directly. According the system, a passive design concept is adopted, the external power is not required, the passive elimination of the molten salt reactor residual heat under accidental working condition is realized by relaying on the natural circulation of the air and molten salt, besides, the space of the molten salt is saved by the system, and the arrangement of the other components is convenient.