We present an accurate parameter extraction method for the HBT large-signal equivalent circuit model in which several extrinsic parasitics are connected to HSPICE BJT model. The measured Gummel plot are used to extract de model parameters of HBT using HSPICE. Capacitances are then obtained from S-parameter measurements of the HBT's biased to cutoff. The other parameters are determined from the active device S-parameters. The large-signal modeled Gummel plot and S-parameters shore good agreement with the measured ones, respectively.