Abstract: During the manufacture of uranium products and nuclear fuel elements, a large amount of uraniferous ash was produced due to pyrolysis incineration of various combustible wastes. In this paper, multi-stage leaching process of uraniferous ash was researched and the effects of ash pretreatment, particle size, leaching times and ultrasonic on the leaching ratio were investigated. The following results are found: (1) the pretreatment method of uraniferous ash has obvious effect on leaching process and drying (120 ℃) pretreatment is superior to the calcination pretreatment ash (800 ℃), (2) the particle size of uraniferous ash has no obvious effect on the leaching process, (3) after first leaching of uraniferous ash, the mass fraction of uranium decreases from about 20% to below 1.5%, reaches to about 0.8% after secondary leaching, and almost remains the same after tertiary leaching, (4) ultrasonic can significantly enhance the leaching of uraniferous ash to reduce the mass fraction of residual uranium from 1.26% to 0.34% after first leaching, and further reduces the value to 0.12% after secondary leaching.