The invention provides a reactor with a passive reactor core waste heat emission function. The reactor comprises a fully-enclosed safety shell. A reactor container, at least one storage tank and a heat insulating layer are arranged inside the safety shell. The storage tanks are used for storing solid heat conduction media. The heat insulating layer is of a fully-enclosed structure, is filled with inert gases and is provided with at least one first outer sidewall connected with the inner wall of the safety shell, at least one second outer sidewall connected with the outer wall of the reactor container and at least one third outer sidewall with one or a plurality of communication valves. A conduction tube extends from each storage tank and is connected with the corresponding communication valve on the heat insulating layer, and each storage tank is communicated with the heat insulating layer after the corresponding communication valve is turned on when a certain temperature is reached or a signal is received. A cooling cycling system for cooling the outer wall of the safety shell is arranged outside the safety shell. The reactor with the passive reactor core waste heat emission function has the advantages that the solid cooling media are adopted to avoid overpressure risks in the safety shell, the system mounting space is saved, and construction cost is reduced.