EAST machine is a fully superconducting Tokamak. It consists of more 20,000 parts and possesses the configuration of 7600 mm in diameter, 6600 mm in height and the weight of 400 tonnes. The complicated general assembly of EAST began in July of 2003 and nearly took two and half years. During the process, not only a series of common difficulties for a large Tokamak but also many technique problems for a superconducting Tokamak itself needed to be solved properly. This paper emphasizes on some key technology issues that were faced and solved in EAST assembly process including optimization of assembly procedure, survey and alignment, ensuring of thermal insulation gap, installation of unique parts, treatment of electric insulation, improvement on heat conduction, control on deformation of vacuum vessel, etc. Besides, the quality control (QC), which made important contributions to the general assembly is also described.