The desulfurization of coal is a pre-processing in order to achieve clean fuel and reduce environmental impacts. In this research, the different coals from Myanmar were collected and each of them was grind and separated in various sizes. The obtained different mesh sizes of Myanmar Coals were leached with H2O2/H2SO4 at different temperatures (65ºC, 75ºC, 85ºC and 95ºC) and different leaching time (10 min, 20 min, 30 min, 40 min and 50 min). The samples after removing sulfur were tested how much sulfur content decrease. In this processes, effects of the leaching temperature, agitation time and particle size on the removal of different forms of sulphur from Myanmar coals were very significant. The optimum values of leaching temperature, agitation time and particle size of coal were obtained for this processes. The calorific values of coals which have leached were compared with that of Myanmar original coals. It can find how the leached coals effect to calorific values of it in burning.