The invention discloses a waste heat removal system for a nuclear reactor. The waste heat removal system comprises a primary loop non-safety stage waste heat removal subsystem, a primary loop safety stage waste heat removal subsystem and a containing body passive cooling subsystem, and the three subsystems are connected in parallel and work according to the safety accident level. Normal shutdown under no accident is carried out through waste heat removal of the primary loop non-safe stage waste heat removal sub-system; when a secondary loop of the reactor is subjected to an accident or a whole plant is powered off, a non-safety stage waste heat removal system cannot be used, and at the moment, the primary loop safety stage waste heat removal subsystem discharges waste heat and is used; when the accident is serious, the containing body passive cooling subsystem is triggered to work. The system is simple and diversified and is provided with a plurality of barriers to discharge waste heat, all the subsystems are mutually independent and are complementary in function, parallel-connected redundant waste heat removal channels can be established between a reactor core and a final heat trap, and it is ensured that the reactor is effectively cooled.