In this paper, the application of a new rock mass classification system QHLW in the site selection of China’s underground research laboratory was presented. The QHLW system considers both the long-term safety and constructability requirements of the host rock for geological disposal of high-level radioactive waste. Compared to the conventional Q system, some additional parameters, including the fracture zone, groundwater chemistry and thermal effect are taken into account in light of their significant influence on the long-term safety of geological disposal. By using QHLW system, the suitability of 9 candidate sites of the underground research laboratory for geological disposal in China was quantitatively evaluated. According to the classification results, Xinchang site located in Beishan area is considered to be the most suitable site.