Abstract: PCMW engineering method is a new support form and has been applied in foundation pit engineering. On basis of situ inclinometer data measured from an excavation case in Nanjing, the deformation curve is fitted by the least squares method, and bending moment value of pipe pile is obtained through inversion calculation. Then security of the supporting form is assessed and its feasibility is verified for foundation pit engineering. The results show that the polynomial optimal times for the least squares fitting curve is 6 times and the bending moment obtained by back analysis can well reflect the actual moment of the retaining structure in middle depth of the foundation pit. The internal forces of supporting pile play a low degree, so safety margin is large. It is concluded that PCMW engineering method on retaining structure is safe.