SBA-15, SBA-16 and crystal like-SBA-16 were synthesized by a simple chemical method, and the copolymer template was removed by calcination or microwave digestion (MWD) method. They were investigated as humidity sensing materials at room temperature within the relative humidity range of 11–95%RH. It was found that after MWD treatment, the humidity sensitive property of mesoporous silica have been greatly improved, and the impedance of MWD-crystal like SBA-16 changed by more than three orders of magnitude over the whole humidity range. Further testing proved that it is a promising humidity sensing material and can be widely used. A possible mechanism was also proposed to explain the correlation between material and property.