Abstract: A domestic copper mine adopts the underhand drift cut-and-fill stoping technology. To meet the strength requirements of cemented backfilling during the mining process, the fluidity tests and strength ratio tests are carried out on the backfilling slurry prepared with aggregates of different gradations. It is revealed that the backfilling concentration is the main factor affecting the flow performance of the backfilling slurry. Moreover, increasing the content of coarse aggregates can enhance the transportation concentration of the backfilling slurry, and simultaneously improve the strength of cemented backfilling. Combined with the requirements of the underhand drift cut-and-fill stoping process, the optimal transportation concentration of the backfilling slurry for the tailings is determined to be between 68% and 72%. When the tailings-crushed stones ratio is 6∶4, the optimal transportation concentration is between 72% and 76%. When the tailings-crushed stones ratio is 4∶6, the optimal transportation concentration is between 74% and 78%. Based on the comprehensive analysis results, the backfilling parameters of the underhand drift cut-and-fill stoping are recommended. For the bottom layer, the tailings-crushed stones ratio is 4∶6 to 6∶4, the backfilling concentration is 76%, and the ash-sand ratio is 1∶4. For the top layer, the tailings-crushed stones ratio is 4∶6 to 6∶4, the backfilling concentration is 76%, and the ash-sand ratio is 1∶8.