In order to verify the reliability of the circuit， the microwave performance for InP HBTs is analyzed based on Monte-Carlo method. The larger the fluctuation range is， the higher the accuracy of extracting intrinsic parameters is required. The allowable accuracy range can be inferred from the output performance. The microwave characteristics are composed of modeled S-parameters， current gain cut-off frequency and maximum oscillation frequency. The standard deviation of Monte-Carlo numerical analysis can be derived from the uncertainty curve of the intrinsic parameters of the π-topology small signal model. The results of Monte-Carlo analysis show that the requirements for the accuracy of measurement parameters are quite different under different frequencies and bias conditions， which verifies the reliability of the circuit under different conditions.