Abstract:  In view of the problems of repeated mining in both the upper and lower No.3 coal seams in one mine under the Weishan Lake，Shandong Province，we measured the ground movement and deformation values of lake area with GPS-RTK technology，monitored the heights of water flowing fractured zone in the mining of both upper and lower No.3 coal seams using the technology of double-head water-stopped machine of upward drill holes under the well，and established the fitted function of surface subsidence and horizontal movement．Moreover，the functional equation of intermediate layer and strata movement boundary in the repeated mining of upper and lower No.3 seams was set up by use of FLAC3D，which reveals the characteristics of surface movement and strata deformation in repeated mining of upper and lower No.3 seams in south Shandong mining area．The study is significant for the safety mining under water，and has a certain reference value for the mining areas with the similar geological and mining conditions．

Key words: surface deformation, water flowing fractured zone, numerical simulation, fitted function