The environmental regulations in the world has been reinforced and many nations has devoted themselves to the development of cost-effective technology. Selective catalyst reduction(SCR) and selective non-catalyst reduction (SNCR) processes are mainly used to treat nitrogen oxidants generated from fossil-fuel combustion. One of these typical technologies for reduction of do-NOx is SNCR process has increased continuously because of the low cost for building and maintenance. Nevertheless the researches on the application to real scale plant by the reductant like Urea are rarely studied. In this paper, an experimental investigations were performed on the SNCR process in the industrial waste incineration plant. With no reducing agent, the concentration of NOx stayed in around 180 ppm $(O_2;12\%)$ with the exhausting temperature of $950^{circ}C$ and changed within the range of 20 ppm to remain relatively consistent. When $10;wt\%)$ of a solution was added, the efficiency of denitrification reached above $61.4\%$ with the NSR of 2.0 and the exhausting temperature of $950^{circ}C.$ When the concentration of the urea solution was set to $10;wt\%$ and the sprinkling to four nozzles, the reaction temperature was reduced to about $50~100^{circ}C$ with a mixture of $10;wt\%;CH_3OH;and;5wt\%;Na_2CO_3$ in $40;wt\%$ of the solution. The NOx removal efficiency increased to $78.4\%,$ achieving a broader and expansive range of reaction temperatures than the addition of an unmixed pure solution.