To study the molten salt cleaning process of carbon deposition on remanufacturing engine valve, a experiment scheme was designed by the Minilab, the experimental data were fitted and the response surface models were built. The influence of the formula and temperature on the ability of molten cleaning carbon deposition was studied. The cleaning effect is tested by cleanliness testing equipment. The results show that with increasing NaNO2 mass fraction, NO-2 can react with a variety of organic matter, its efficiency is much higher than the NO-3 with C , and OH- with organic. The temperature affects not only the thermal shock, wetting and other effects, but also the rate of chemical reactions. Thus, with increasing temperature and mass fraction of NaNO2, the cleaning effect is reinforced. The optimal parameters of molten salts cleaning is the temperature of 330360 ℃, NaOH mass fraction of 30%, and NaNO2 mass fraction above 40%. As an efficient and cleaned method, molten salt cleaning technology can be widely used in the remanufacturing production.