Based on the theoretical derivation, the distribution law of the grouting pressure of the underground road during the construction of the shield tunnel in three-sided enveloped space was obtained. The reasonable grouting pressure was calculated and the influence of the grouting pressure on the structure of the underground tunnel was discussed. The results show that the grouting pressure can offset the structural deformation caused by the shield tunneling and even generate new additional deformation. When the soil loss rate is larger, the influence of the grouting on the structure of the underground road is greater.