The slurry pressure control is the key to excavation face stability during superlarge slurry shield tunneling. Based on the Beiheng Tunnel in Shanghai under construction, a determination method for slurry pressure on excavation face of supperlarge slurry shield tunnel in composite ground is summarized by threedimensional numerical analysis method. The results of the method application are compared with the site monitoring data. The study results show that: (1) The optimal balance between slurry and pressure is related to the thickness ratio of soil layer and the effective internal friction angle of upper and lower soil layers. (2) In the approximate uniform stratum, the shield center point can be selected as the balance point, which is in accordance with engineering experience in practice. (3) In the composite ground, the optimal balance point can be determined by theoretical calculation.