Coal ash belongs to a kind of mixed material like pozzolana, which is formed after the combustion of the pulverized coal at high temperature. China is the No. 1 coal production and use country all over the world, and the coal ash produced from burning coal accounts for about 30% of the total fire coal. How to use cumulative secondary resources well, reduce floor space and environmental pollution, create higher added value, and comprehensively utilization of coal ash obtains more and more attention from people. This article describes the composition nature of coal ash and comprehensive utilization status quo in construction, building materials, agriculture, environmental protection and chemical industry, and makes recommendations on the problems and development trend of coal ash in China.