Microcrystalline cellulose was reacted with catalytic amounts of 2, 2, 6, 6-tetramethyl-1-piperidine oxoammonium salt (TEMPO), sodium hypochlorite and sodium bromide in $Na_2CO_3/NaHCO_3$ buffer solution at different temperatures ($30^{circ}C$, $40^{circ}C$, $50^{circ}C$). The oxidation procedures included first oxidation and second oxidation. The yield of cellouronic acid produced in the second oxidation was higher than the yield of cellouronic acid produced in the first oxidation at the same oxidation temperature. Moreover, an interesting "high-hydrophilic" phenomenon appeared at higher temperature during microcrystalline cellulose second oxidation ($30^{circ}C$, $40^{circ}C$, $50^{circ}C$). Properties associated with the chemical characteristics are discussed by XRD, FTIR, $^{13}C$-NMR and Laser Particle Analyzer in view of its interesting high-hydrophilic effects.