The oxidant ClO- was generated on an SPR (SnO2-PdO-RuO2-TiO2) anode and used to degrade formaldehyde in aqueous solution. The current efficiency of the production of hypochlorite ion was significantly affected by the concentration of chloride ion, pH and stirring rate. The effect of current density and temperature on the current efficiency for electrogeneration of hypochlorite ion was slight. The maximum anodic current efficiency was 99.3% when 100 C was charged. Increasing the concentration of chloride ion, pH, temperature, stirring rate and the concentration of formaldehyde in the solution and decreasing the current density and charge passed resulted in increased current efficiency of degradation of formaldehye with electrogenerated hypochlorite ion.