Abstract: For status that coal ash content analyzers cannot be used in coal mine underground at present, the paper proposed a whole design scheme of explosion-proof coal ash content analyzer, and pointed out that key technologies of the content analyzer are ray penetration window technology and intrinsically safe power supply technology based on change rate detection of current. It proposed technical requirements of ray penetration window based on research of ray attenuation characteristic of coal ash content analyzer, and a new method of choosing materials of ray extraction window through theoretical analysis and tests, which solves problem of large attenuation rate of γ ray with low energy through explosion-proof enclosure and ensures precision of the coal ash content analyzer. The paper also proposed the intrinsically safe power supply technology based on change rate detection of current on the basis of research of influence of load characteristics of intrinsically safe devices on performance of intrinsically safe power supply, which overcomes shortage of current delay of inductive load and improves reliability of the coal ash content analyzer. The application of the coal ash content analyzer in coal mine effectively reduces waste discharge.