In this research, five layers of alumina doped with different amounts of molybdenum (0, 0.5, 1, 2, 5 wt%) have been coated on 316L stainless steel substrate using the sol gel process for increasing the corrosion resistance of 316L stainless steel in the molten sulfur environment. Thermal Analysis (TG-DTA) of the coatings showed that by increasing the percentage of molybdenum in the coatings, the crystallization temperature of alumina phase shift to lower temperatures. X-ray diffraction results showed that increasing the percentage of molybdenum, would result in decreasing the amorphous to crystalline transition temperature. Also, by increasing the molybdenum content, in addition of alumina peaks, the Al/Mo oxide compounds have been appeared. The results showed that with increasing the molybdenum content, the grain size in the crystalline phase increases. EDS analysis also revealed that by increasing the percentage of molybdenum in the coating solution, molybdenum of coating powder has been increased. Using the scanning electron microscopy (SEM), uniformity, homogeneity, and absence of cracks in the coating that have been calcined at 450 ? C relative to 750 ? C has been indicated. By measuring the thickness of coatings, the average thickness of 154 nm was obtained. Electrochemical impedance spectroscopy (EIS) tests in 3.5 wt% NaCl solution showed that the calcination temperature of the substrate at 450 ? C reduces the polarization resistance, but in the case of coatings, sintering process, increases the polarization resistance. Addition of molybdenum reduces the polarization resistance compare to pure alumina coating, but compare to the substrate, the polarization resistance has been increased. Potentiodynamic polarization tests have been shown that the substrate calcination reduces the corrosion potential and increases the corrosion current density. Cyclic polarization test on the coatings doped with molybdenum showed that the addition of 1 wt% molybdenum reduces the corrosion current density, but increasing more than 1wt% Mo, result in further increase in current density. However, the current density is much lower compared to the substrate. In other words, the best conditions for corrosion resistance in an aqueous solution of sodium chloride in two percent molybdenum has been occurred. Scanning electron microscopy after the electrochemical tests, compared to the coated, substrate showed severe pitting corrosion. Adding molybdenum reduced the severity of pitting corrosion. So that at about one percent molybdenum, the lowest corrosion has been occurred. Scanning electron microscopy of samples in liquid sulfur at 200 ? C showed that with increasing of molybdenum, severity of the corrosion has been reduced so that the alumina doped with 5 wt% molybdenum has shown the least corrosion. Scanning electron microscopy of the surface of the coatings after placing the samples in 300 ? C liquid sulfur showed that at this temperature the pitting corrosion is not seen and uniform corrosion was replaced with pitting corrosion. By increasing of molybdenum as doping agent in the coating, the uniform corrosion intensity decreased, so that in the case of alumina coating doped by 5 wt% of molybdenum, the corrosion has been diminished. Keywords: Alumina, dopant, molybdenum, sol- gel, dip coating, calcination, electrochemical properties, molten sulfur.