The connection section between left line of Line No. 2 of Zhengzhou Metro and connecting tunnel of Line No. 1 and Line No. 2 are constructed together. The surrounding environment is complicated and the construction schedule is tight. The large crosssection tunnel construction technology, mining method, is adopted to enlarge the shield tunnel. The section is bored by shield, and then the steel segments, the bench method of central pillar + temporary invert and inverse enlarging method are adopted. The construction practice shows that the ground settlement and the construction schedule have been controlled effectively. The abovementioned technologies can provide reference for similar projects in the future.