Abstract: Aiming at the issue that the control performance of Boost converter is affected by inductance and capacitance variations, this paper proposed a variable forgetting factor RLS based online multiparameter identification algorithm. Considering the inductor current ripple, an accurate inductance and capacitance identification model was derived. On this basis, the dynamic value of forgetting factor in RLS algorithm was studied. By recovering system noises in the error signal of the algorithm, the value of forgetting factor was dynamically calculated, which solves the problem that the traditional RLS algorithm cannot balance steady-state accuracy and parameters tracking ability. The simulation results show that the algorithm can track the variations of inductance and capacitance accurately and quickly under dynamic condition, and has good robustness.