The No. 6 bid section of Harbin railway transit No. 1 line is a tunnel rehabilitation project with 1 500 m length. The surrounding environment of the existing tunnel is complicated. Single side enlarging and local double side enlarging method is adopted. In the paper, the settlement essence is analyzed. The influencing factors and countermeasure of settlement are analyzed in term of humanmachineenvironment system. The settlement control target and process are analyzed. The determination, carrying out and effect estimation of settlement control technologies are analyzed emphatically. The paper can provide references for similar projects in the future.