Abstract: In order to improve the mining rate and control the coal rejects rate, a mine flame proof coal ash analyzer was required to on-line monitor and measure t he ash content of the raw coal from the mining face According to the status of the 24 1Am low power y rays applied for the ash analyzer would be reduced by 94.1% afte r the rays penetrated through a 3 mm steel plate, a ray penetrated window technology was provided.With a study on different materials and the several experiments and comparisons, a penetrated window material with the flame proof performance requirements was found and the reduction rate of the low power γ ray could be reduced to 40.6% after penetrated through the explosion proof shell.With the selection of the double sources divided device, the double y rays detector technology could eliminate the 137Cs Compton effect affected to 24 1Am counting number and could solve the non-consideration contradiction in the scope of the Cs and Am counting numbers.Th e mine coal ash analyzer designed with the double γ rays technology was applied to the Tiefa, Jiaozuo, Yanzhou and other coal mining group.The site measurements a nd tests showed that the accuracy could meet the requirements of the custmers.