Carbon pyrolysis is one of the essential ways to improve carbon energy utilization and reduce environmental pollution. The main product of carbon pyrolysis process is tar, and improving tar yield can not only increase the resource utilization efficiency, but also reduce the pollution to the environment. Therefore, this paper investigates the application of Ni/MgO catalyst in the pyrolysis process of bituminous coal. The experimental results show that Ni/MgO catalyst can effectively activate small molecule radicals and make them combine with prominent molecule radicals stably to improve the tar yield. Meanwhile, when it is under the pyrolysis gas environment, pyrolysis temperature reaches 570 ℃, gas flow rate is 375 ml/min, and the catalyst is selected to be filled in the upper layer, the activation effect of Ni/MgO catalyst is more prominent, and it can significantly increase the tar yield and the proportion of light oil. Ni/MgO catalyst had the best effect in tar yield increase compared to other catalysts, but the performance was average in fair oil percentage increase. The catalyst could also reduce the number of aliphatics in the tar and increase the proportion of non-aliphatics, improving the tar quality.