The research of key technologies for largediameter slurry shield under shallowburied strata in flourishing city in China is weak. Study and analysis are made on large diameter shield launching in shallowburied strata, deformation prediction of railway bridge and optimization design and adaptability improvement of slurry separation system by taking underground tunnel on North Huancheng Road in Hangzhou for example. The study results show that: 1) The consolidation length of end soil should be larger than shield body length about 1 ring length. 2) The measured deformation results coincide with the theoretical prediction results, so as to verify the importance of theoretical predictions. 3) The slurry separating effect has been significantly improved by increasing rods and modifying the lower vibration screen, etc.