Abstract: The existing field measurements show that the deformation of retaining wall and surrounding environment induced by pre-excavation dewatering can reach centimeter level, but the relevant researches are still less. The behaviors of pit deformation induced by pre-excavation dewatering are not been fully revealed. In this study, a two-dimensional fluid-solid coupled finite element model is established using ABAQUS to investigate the influences of excavation width and dewatering depth on wall deflection. The results indicate that the maximum wall deflection (δ_hm) and the distribution range of wall deflection along depth (H_c) become larger with the increase of excavation width and dewatering depth. There is a critical excavation width, within which δ_hm and H_c increase fast with the increase of excavation width. However, with the excavation width being greater than the critical excavation width, the influences of excavation width on wall deflection are weak obviously. Besides, there is a critical dewatering depth, within which δ_hm change slowly with the increase of dewatering depth. However, with the dewatering depth being greater than the critical dewatering depth, the increase of dewatering depth will lead to a substantial growth of the maximum wall deflection.