The accurate diagnosis of burn depth is one of the important problems in the field of burn surgery. The diagnosis accuracy rate is directly related to the treatment plan and effect. The existed clinical diagnosis methods mainly depend on the experience of burn surgeon, making the accuracy rate from 50% to 65%. In order to improve the accuracy rate of clinical burn depth diagnosis, a large number of diagnosis methods based on imaging are proposed, however, all of the methods are still in the stage of experimental research. In this paper, the research advances on the diagnosis techniques of burn depth are summarized, both the advantages and the shortcomings are pointed, and the development trend of diagnosis techniques of burn depth is expected.