Carbothermal reduction and nitridation (CRN) of zircon (ZrSiO4) permits obtaining different composites of oxides and nitrides such as ZrO2-Si2N2O and ZrN-Si3N4. The effects of technological parameters (carbon source, reaction temperature, and carbon content) on the reaction rate and product phase composition of CRN of zircon were investigated by TGA and XRD. The results show that: (1) carbon source is an important factor for a rapid reaction, and activated carbon is chosen as the carbon source considering the expect products and reaction rate; (2) reaction temperature has vital effect on reaction rate and product. In case of carbon content above 20%, the zircon phase and m-ZrO2 phase decrease with increasing temperature, while the Zr7N8O4 phase increases firstly and then decreases, and the ZrN phase increases continually; (3) different carbon contents result in different reaction products. The higher the carbon content, the lower the starting temperature for the CRN of zircon.