Abstract: In this paper, based on the measured reinforcement stresses in the retaining piles for the deep excavation in Chengdu Jinyang Trade Mansion, the corresponding bending moments in the piles are found Then the deformation condition of the retaining piles is examined It is indicated that the ring beam on top of the piles has appreciable restriction effect which prevent the tops of the piles from displacing and rotating freely So the behavior of the retaining piles under lateral pressure is quite different from that of the upright free head shaft Taking the moments found from the reinforcement stresses as the measured values, and the moments computed by considering the top restraint forces as the calculated values, the distribution and value of the earth pressure above the excavation surface on the retaining piles are back analyzed by means of the method of least squares The results are quite different from those obtained by the classical Coulomb′s or Rankine′s earth pressure theory