To analyze the excavation deformation low of pile-anchor combined support structure foundation pit in soil-rock dual stratum with large geological fluctuations under complex working conditions，in light of the measured data of an open-cut foundation pit engineeringt in Xiamen ，the pile top displacement，pile lateral displacement，surface settlement outside the pit and anchor cable internal force were studied.The findings reveal that：According to the difference of geology and the rock-socketed of the pile bottom，the lateral displacement of pile body can be divided into“cantilever shape”，“cantilever shape + kicking shape” and “translational shape”.The maximum lateral displacement value of pile body is between 0.34%H and 0.58%H，and the mean value is 0.48%H.The surface settlement pattern shows a concave - shaped distribution，and the positiont with the largest settlement is approximately 0.33H from the edge of the pit，and the maximum surface settlement δvm is between 0.5δhm and 2.5δhm.The overall ability of pile-anchor supporting structure to resist the deformation of foundation pit is insufficient，and the deformation of foundation pit will increase sharply when the prestressing force is not stretched in time.The high pressure rotary grouting after the retaining pile will aggravate the deformation of the foundation pit.In similar projects，it is suggested to take reinforcement approaches with less disturbance to the soil，such as MJS grouting reinforcement