Abstract: There are large range of water seepage and inflow in surrounding rock mass of tunnels during deep mining of Sanshandao gold mine.As the undersea mining，it is necessary to find the rule and feature of water seepage and inflow for ensuring the safe mining.Through analyzing monitoring results of water inflow in multi-level areas，the dynamic law of water inflow in the mine is revealed.Meanwhile，the chemical component of mine water from 15 representative water samples in the range of -510 m to -725 m is analyzed.It is found out that the underground water is mainly Cl-Na water.In mineralization property，it belongs to high-salinity saline water.And the chemical damage of rock mass lead by high-salinity water will affect the stability of deep stoping.Numerical simulation by the software FLAC3D is conducted on deep mining of Sanshandao gold mine to analyze the distribution characteristics of water seepage field.The result shows that the variation of pore water pressure mainly occur in excavation areas.In addition，the variations of water seepage field have already expanded into F₃ fault area in which the variation gradient of pore water pressure and seepage pressure are great，which forms high seepage pressure.Therefore，water plugging and intensive reinforcement are needed in the mining process.

Key words: Deep mining, Water seepage, Chemical damage, FLAC^3D