Abstract: The barrette diaphragm wall has a large aspect ratio, superior load-bearing performance, fast construction speed and good engineering application prospects. However, its bearing mechanism is not yet clear. By establishing a numerical model for the foundation with the barrette diaphragm wall, the vertical bearing characteristics and the wall-soil interaction mechanism are studied. The influences of wall parameters, soil parameters and other factors on the vertical bearing capacity of the barrette diaphragm wall are analyzed. The calculated results show that increasing the burial depth of a single diaphragm wall by 10 m can increase the bearing capacity by 34% to 60%. An increase of 12 m in the wall length can increase the bearing capacity by 14% to 89%. The bearing capacity of the diaphragm wall increases linearly with the increase of cohesion and internal friction angle of the soils, and logarithmically with the increase of elastic modulus of soils. When the load on the top of the wall approaches its limit, a potential conical sliding surface forms near the wall base. The longer the length of the diaphragm wall, the greater the impact of the diaphragm wall on the surrounding soils, and there are superimposed effects between the wall amplitudes on the surrounding soils.