Abstract: Comblike branched polystyrenes with different branching structures were dissolved in tetrahydrofuran (THF), and root mean square radius of gyration (Rg) and intrinsic viscosity (［η］) in solution were measured using multidetection GPC with refractive index, viscosity and multiangle lightscattering detectors (GPC-RI-MALLS-DV). Results showed that Rg and ［η］ of comblike branched polystyrene increased with the increasing of branch lengths and branch numbers, and demonstrated linear relationship with molecular weights. However, as the branch lengths and the branch numbers increased, the increased trend of Rg and ［η］ with the increasing of molecular weight slowed down gradually. The influence extent of branch numbers on Rg and ［η］ was larger than branch length. In addition, the values of K and α of the MHS equation parameters of comblike branched polystyrene in THF changed with the increasing of branch lengths and branch numbers.