In recent years, shielddriven method witnesses a rapid progress in urban tunnels in China, especially in urban sewage tunnels, water and power supply tunnels and gas supply tunnels, to which small diameter shields are widely applied. The paper briefly introduces the launching technique, one of the crucial techniques, of the long and thin mudshields with small diameters in different strata through example projects to analyze and compare the strong points and weak points of different plans for your reference.