During the construction of the underground space of the rectangular pipe jacking with a large section, a large amount of soil below is lost, which cannot be ignored to the surrounding soil Sedimentation occurs depending on the disturbance. Now, depending on a large cross-section rectangular pipe jacking project in Suzhou, the lateral settlement of the monitoring section is predicted through the peck formula and the random medium theory respectively, and the comparative analysis shows that the modified peck formula is more consistent with the measured value; The daily settlement data of the monitoring section are analyzed and compared to verify that the mud slurry injection during construction has a significant control effect on the formation settlement.