Abstract: The computational simulation for highfrequency characteristic of helical slowwave circuit using MAFIA software avoids the assumptive theory conditions, improving the calculation precision. Compared with the experiment data, the average error of dispersion simulation result reachs less than 1%, and that of impedance reachs less than 0.2%. Compared with the calculation time and precision using the different simulation method in the different modeling method, the quasiperiodic boundary conditions is proved a simulation method of satisfying precision and efficiency demand in practical engineering application.