Organic hazardous compounds were analyzed and investigated the leaching possibilities for environmentally sound recycling of coal ash. Coal ash generated by power plant of coal would be remained of hazardous substances as Dioxins in ash from incinerator. 33 samples (8 coal and 25 coal ash) were collected and analyed dioxins, PCBs, HCB, PAHs and phenols as hazardous substances by GC/HRMS, GC/ECD, and GC/MSD. In coal ash samples, Dioxins were detected in the range of 0.002 to 0.019 ng/g and co-PCBs detected in the range of 0.005 to 0.042 ng/g but HCB, PAHs, phenols was were not detected. Therefore recycling of coal ash would not affect environmental pollution. In coal samples, Dioxins were detected in the range of 0.016 to 0.090 ng/g, co-PCBs in the range of 0.056 to 0.173 ng/g and PAHs detected in the range of 0.00 to 9.27 ng/g but HCB and phenols were not detected. In the case of PAHs, the concentration in bituminous coal was higher than anthracite coal. Comparing to waste and soil, the concentration of Dioxins and co-PCBs in coal ash was very low. No significant environmental risk is expected from the use of coal ash as filling materials to soil by the substances.