The invention relates to a method for measuring the density and temperature of heat flux of a hot side of a crystallizer, and belongs to the technical field of continuous casting. The method includes the steps of reasonably installing two thermal couplers in the continuous casting crystallizer to acquire temperature data, and then converting the acquired temperature data in the walls of the crystallizer into the density and temperature of heat flux of the hot side of the crystallizer through a two-dimensional heat transfer inverse problem. The method has high industrial application value, and the density and temperature of heat flux of the hot side of the crystallizer can be more accurately calculated.