From the previous study the white dot is represent for the hot-compressed water and the black dot is represent for the hot-compressed water with 3 percent weight as an catalyst. After plot, the hot-compressed water with severity function and hot compressed water with sulfuric as an catalyst data and fit the curve it was found that yield of a xylo-saccharide of two experiment is similarly. According to the assumption if the yield of xylo-saccharide is similarly the severity index should be the same. But the severity index of these two experiments is not even close. This is the reason why this study aims to develop a modified severity parameter to use with any conditions. Which contains hot-compressed water, hot compressed water under pressurization of carbon dioxide. Hot-compressed water with organic acid and in organic acid.