Shear thickening liquid (STF) is a novel functional material. It presents as the liquid in normal state, but shows a solid performance when subjected to the external impact. According to the feature, it can be used as bullet-proof materials. While STF in low shear rate, there will be a shear-thinning phenomenon, while in the high shear rate, there will be a shear-thickening phenomenon. A high performance STF is being developed by using the Nano-silica as the dispersed phase and a polar solvent as the dispersion medium.