Abstract: According to the actual situation of the mine，the influence of filling concentration，lime sand ratio，coarse aggregate content and curing age on the uniaxial compressive strength of cemented back⁃ fill was studied by using orthogonal experiment method. The results show that the strength of backfill in⁃ creases with the increase of filling concentration，curing age and lime sand ratio. As the fine particles of tailings cannot effectively fill the gap between the coarse aggregates，the strength of the filling body de⁃ creases with the increase of the coarse aggregate content in the range of 70%~85%. The optimum content of coarse aggregate is 70% under the existing conditions，but there is still room for further optimization of the type and grading of coarse aggregate. The range analysis results show that the lime sand ratio has the most significant effect on the strength of backfill，followed by the filling concentration and curing age. In prac⁃ tice，the filling concentration and curing age should be increased as much as possible，and different lime sand ratios should be adopted for different positions of goaf to achieve the purpose of improving the filling strength and reducing the cement cost. The research results can provide guidance for mine filling practice.

Key words: cemented fill, orthogonal experiment, compressive strength, evolution law, proportion opti? mization