The main synthesis of single-walled carbon nanotubes (SWCNTS) on a large scale and in higher purity is investigated. To analyse the characteristic of different synthesis and the major parameters whose variety influence the product. The kinds and ratio of carbon source and catalyst influence the preparation of SWCNTS obviously.The factors such as current and voltage,the kind of inert gases and pressure and the cooling rate of electrodes play important roles in synthesis of SWCNTS by arc discharges. The intensity of laser bean,environmental temperature,the kind and the velocity of flow of catalyst and the frequency and interval of impulse act important parts in SWCNTS produced by laser evaporation. The flow rate of carbon resource, the grain sizes of catalyst,reaction temperature,the gases pressure and flux and matrix materials etc play key parts in SWCNTS synthesized by chemical vapor deposition.