Abstract: In order to study the fault hydraulic conductivity,two mining area boundary faults,F5 and DF5-21 in Qidong coal mine Ⅱ3 mining area,were used as background,and the lateral and vertical closure of the faults were studied quantitatively on the basis of qualitative research using SSF,CSP,SGR integrated analysis method and positive pressure discriminant method of the fault surface respectively.The hydraulic conductivity of the mining area boundary faults was evaluated.The results show that the fault distance is the main influencing factor of the lateral closure of the fault.With the increase of the fault distance,the mudstone coating distance becomes longer,the lateral closure of the fault becomes worse,resulting in better lateral hydraulic conductivity of the fault.The positive pressure of the fault surface is the decisive factor affecting the vertical closure of the fault,with the increase of the burial depth of the stratum,the positive pressure of the fault surface increases,the vertical closure of the fault becomes better,resulting in worse vertical hydraulic conductivity of the fault.The research results can provide relevant reference for water control in coal mines.