Non-thermal plasma has been widely investigated to apply to environmental protection. The effectiveness of electrical discharge technology on decomposition and transformation of toxic gases has been widely studied, while its influence on the toxic substances in fly ash is not clear. In this paper, the surface chemical transformation of fly ash from electrostatic procipitators has been studied by surface pulse discharge. A surface mechanical change and a destruction of powder particles were visible after discharging. This indicates that the pulse discharge causes an effective desturction of the fly ash powder and its particles. The composition analysis showed that volatile organic compound (VOC) content in sampies decreases after discharging. A positive pulse discharge showed a higher decrease in VOC content than that of a negative one did. We concluded that by using the surface pulse discharge, especially in the case of positive pulse discharge, the non-thermal plasma is also effective on decomposition and transformation of toxic substances in fly ash, which reaches a 51% VOC decomposition effectiveness.