The type selection design of shield is very important to shield construction of metro; it directly affects the success of the construction. The Line No. 2 of Nanning metro crosses complex geological conditions, i. e. clay, hard rock, gravel, uppersoft and lowerhard stratum and karst stratum. As a result, the general requirements for shield type selection are put forward in terms of power device, cutterhead and cutter; meanwhile, the design of mud cake prevention, screw conveyor, small angle belt conveyor and synchronous grouting system and geological reinforcement methods are optimized. Finally, the actual tunneling parameters and ground surface settlement data show that the adaptability of the shield machine in Nanning area is good.