Tc-99m is an extremely useful tool for medical diagnosis because it has good nuclear properties, and the radioisotope Mo-99 is the only parent nuclide. Mo precipitation process by using α-benzoin oxime can be used as one of processes for separation & purification of fission ＾99Mo. In this study, the recovery yield of Mo in sulfuric acid solution by precipitation reaction were investigated to obtain optimum operating condition and process design data. In the results of experiments, recovery yield of Mo could be maintained above 95% in condition of 1-1.5N free acidity of Mo solution, 25 B.O./Mo weight ratio and dissolution time 25min.