The present invention discloses a parameter tuning approach for bypass damping filter to suppress subsynchronous resonance in power systems, namely determining the parameters of capacitor, inductor and damping resistor in BDF. Using this approach, the parameters of capacitor and inductor in BDF can be adjusted, so that the frequency where the negative electrical damping of generator reaches minimum can be away from the frequency range of low frequency oscillation mode and typical frequencies of each torsional mode; the parameter of damping resistor in BDF can be further adjusted so that the minimum value of negative electrical damping is in reasonable range. The application of BDF with parameters tuned by the present invention contributes to the suppression of both the torsional interaction effect and the transient torque amplification effect.