Reburning is a process whereby a hydrocarbon fuel is injected immediately into the downstream combustion zone to establish a fuel-rich zone in order to convert NOx to N2. The kinetic mechanism of NOx reduction with natural gas reburning is analyzed. The key parameters influencing the reburn process are described. It has been found that to achieve a relatively high NOx reduction, proper values should be selected as regards the following parameters: temperature, residence time, stoichiometric ratio in reburning zone, as well as an optimal position of natural gas injection. It is predicted that there is a potential for wide application of natural gas reburning technology in coal-fired utility boilers in China.