In the paper, feasibility analysis and expatiations are made on basis of the structural features of different types of shield machines. On basis of analysis on the relations between the shield machine types and the ground permeability coefficient, clay content and grain size grading, detailed expatiations and comparisons are made on the type selection of shield machines in respect of working face stability mechanisms, ground settlement, installation power, cutter wearing, construction cost and construction progress. Furthermore, discussions are made on the key construction technologies of shield machines.