The mechanism of the oxidation, nitration, and hydrolysis process of isopropanol with fuming nitric acid (98%, white) was studied by C-13 NMR spectroscopy. The effect of the nitronium (NO2+) on the preparation of nitroform from isopropanol was investigated by using fuming nitric acid and H2SO4-HNO3 as nitrating agents. The results indicated that fuming nitric acid showed a better efficiency for the studied reaction. Furthermore, the effect of specific factors, such as reaction temperature, reaction time, and molar ratio of nitrating agent to isopropanol, on the yield of nitroform was investigated. Pure nitroform can be obtained under optimized condition with excellent yield of 51.3%, about 26% higher than that reported in literature. Orthogonal experiments were also carried out to further support the effectiveness.