Abstract: Inorganic porous non-metallic ores can be grouped i nto three types according to the size of pore diameter and their applications: n anometer sized (1～100nm), micron sized (0.1～100μm) and millimeter sized (0.1 ～1.0mm). Among them, micron sized porous non-metallic ores chiefly include dia tomaceouse earth, light-weighted opal, porous tuff and siliceous rock etc. Mos t of them occur in activated regions of platform as the results of post-platfor m mineralization　at a stable stage. 　　The principal mineral phase of micron sized porous non-metallic ores is opal, microquartz crystals and rhyolitic glass. The porous siliceous rock mainly consi sts of microquartz crystals and has a high degree of hardness and stability.The opal as a major mineral phase of diatomaceouse earth and light-weighted opal, a nd the rhyolitic glass as a major mineral phase of the porous tuff, are usually unstable. They are very easily to undergo crystallization in nature. 　　Chemically, the micron sized porous non-metallic ores have the features of higher silicon and lower aluminium, iron etc.. Among them the porous siliceous r ock has the highest contents of SiO2 ( >92%), the diatomaceouse earth and lig ht-weighted opal--less　(<92%), and the porous tuff--the lowest(<70%). This is one of the most effective markers to identify porous siliceous rock and diato maceouse earth. 　　There are similar and different aspects in pore features of micron 　sized porou s non-metallic ores. Their similarities are high porosity, low cumulus density and frequent open-pores; Their differences are mainly expressed in size, shape and compression strength of the pores. 　　The micron sized porous non-metallic ores have strong adsorbability and heat p reservation capacity and can be used as the adsorbents， catalysts, carriers, fi llings and thermal insulation materials. Because of their remarkable functio n in removing particles in filtration and separation, they are the best raw mate rials in making filter aids. Presently, most of micron 　sized porous non-metal lic ores as potential non-metallic mineral resources have been gradually utiliz ed in the fields of building materials, chemical engineering, agriculture, food and environmental protection etc.