In recent years，with the increasing depth of underground mining and the increasing probability of accidents such as goaf collapse and surface subsidence，tailings filling has become one of the most popular methods of composite aggregate filling.It can not only effectively limit ground pressure activities，but also be beneficial to tailings treatment and environmental protection in mining areas.However，the damage and destruction of filling body also threatens the safe production of the mine.With the increasing of underground mining depth，the problem of ground pressure is becoming more and more obvious.By using the whole tailings of a mine and 32.5 type cement，the filling specimens with 100 mm \times50 mm （high*diameter） are preparedunder lime-sand ratio of 1∶8，curing age of 28 days，slurry concentration of 66 \mathrm{\%}，70 \mathrm{\%} and 74 \mathrm{\%}.The confining pressure conditions are 0.4，0.7 and 1.0 MPa.The RMT-150C in the Key Laboratory of Mining Engineering of Jiangxi Province was used.The experimental operation was carried out on the hydraulic press.The force （small） -displacement control was adopted in the test process，and the loading rate was 0.002 mm/s.In order to reduce the influence of other factors on the test data，the specimen is regarded as the preparation and maintenance under the same test condition.According to Lemaitre strain equivalence principle，the pre-peak damage value and post-peak damage value are deduced.The damage-strain curves of filling slurry concentration of 70 \mathrm{\%}，damage-strain curves under different confining pressures and different slurry concentration under confining pressures of 0.7 MPa were obtained through experimental data.When the filling slurry is 70 \mathrm{\%}，under the confining pressures of 0.4，0.7 and 1.0 MPa，the corresponding damage values of peak limit are 0.2111，0.2860 and 0.1920 respectively，showing a trend of increasing first and then decreasing.When the confining pressures is 0.7 MPa，under the slurry concentration of 66 \mathrm{\%}，70 \mathrm{\%} and 74 \mathrm{\%}，the damage values corresponding to the peak limit are 0.303，0.286 and 0.275，respectively，and the whole body shows a decreasing trend in turn.From the damage-strain curves，it can be seen that when the slurry concentration is constant，the increase of confining pressure shortens the elastic deformation stage of filling body，achieves the yield limit earlier and the peak damage value increases.Continues to increase confining pressure， the peak damage value of filling material decreases.At low confining pressure，the increase of slurry concentration inhibits the increase of pre-peak damage but promotes the increase of post-peak damage.At high confining pressure，with the increase of slurry concentration，the damage value of filling materials decreases first and then increases，which promotes the failure of the filling specimens.