Different types of anti-explosion fiber used for castables are selected as samples to study and analyze the fiber structure,dry state and water-solubility at different temperatures.The result shows that in drying and heating process,the melting temperatures of 6# and 7# samples are the lowest,as low as below 130 ℃;the carbonation of 5# sample has begun before hardening at 250 ℃;in room temperature water,the dispersion effect of 5# sample is the best;in boiling water,5# sample completely dissolves into water,6# and 7# samples soften and contract into clusters,and the other samples arrange irregularly and gather and float on the water surface.