On the electrolytic preparation of sodium chlorate, lead dioxide anode, instead of graphite was tested to find out the characteristics for current efficiency and life in various conditions. The results obtained are summerized as follows; 1. The current efficiency is slightly increased with the anode current density, until 25A/$dm^2$ 2. The higher the current concentrations. the lower current efficiencies are observed, particularly in case of both not-adding the potassium dichromate and large current concentration of more than 50A/l 3. The current efficiency may be improved linearly as the both temperature is raised.