Abstract: With the increasing of pit-in-pits and the scale expansion of the inner pit, the support of pits-in-pit become an urgent problem to be solved for the frequent occurrence of pit accidents due to the underestimation to the inner pits impact in retailing structure design. In the case of Meizizhou Changjiang-cross tunnel in Nanjing, we analyze the impact of interval between internal and external pits on earth pressure and deformation of retailing structures separating and supporting the internal and external pits by centrifugal model test. The results show that with the decrease of interval, the outside earth pressure on the middle wall gradually increases after the excavation, maintaining above the static earth pressure throughout, and the outside earth pressure near the bottom of the middle wall is close to the static earth pressure of the outside pit; with the decrease of the interval, the horizontal displacement at the left top of the middle wall and the maximum horizontal displacement of the right wall decrease gradually, which is toward the inner side all the time. The variation of the earth pressure is in good agreement with the deformation of the retaining wall.