The present investigation was conducted to study the leaching characteristics of trace elements in coal fly ash and the ash disposal system of thermal power plants. The batch experiment for the fly ash collected from the hopper of the electrostatic precipitator of the thermal power plant, Delhi, was carried out to study the leaching characteristics of Fe, Cm; Cu, Pb, Cd, and Ni. Four leaching time intervals were selected, ranging from l week to 4 weeks. From the experiments, leaching behavior of trace elements was investigated and it was observed that 'Cr' and have a relatively higher leachability in extraction solution than aqueous. and buffer solution. Furthermore, with the leaching time, the leachability of 'Cu' is increased in aqueous and extraction solution. The leachability of 'Cd' increased with leaching time in aqueous and buffer solution. With the increase of leaching time, the leachability of 'Fe' in extraction fluid increased with time with small fluctuation.