Abstract: In order to judge the damage condition of bridge crane, a crack damage detection method of bridge crane was proposed based on the relationship between acoustic emission signal intensity and duration. By comparing and analyzing the correlation point plots of acoustic emission signal duration and signal intensity under different working conditions, a slope trend index for crack damage detection was proposed. An experimental study was carried out on the whole structure of bridge crane girder and the prefabricated crack test pieces of the same material. The experimental results showed that the correlation figures of the faultless crane structure and the defective structure had different slope trends. It provided a method and reference for judging crane damages by using acoustic emission technology.