The principle of MJS (metro jet system) is introduced in detail and a set of parameters of construction and design for MJS pile used in soft soil area in Ningbo is proposed so as to learn influence of squeezing effect of construction of retaining piles on deformation of adjacent existing buildings. The variation laws of settlement and inclination of adjacent buildings, settlement of surrounding ground surface and deformation of deep soil during MJS pile construction are obtained by dynamic tracking monitoring method; and analysis is made on quality of MJS pile. The results show that: 1) The construction of MJS pile affects the environment little. 2) The uniaxial compressive strength of MJS pile is larger than 1.49 MPa when the cement content of MJS pile is larger than 50%. 3)The quality of the MJS pile decreases with the depth of clay increase. 