This paper proposes a parameter tuning method of the extended state observer(ESO), which can expand the disturbance observation bandwidth while suppress the measurement noise effectively. Firstly, the equivalence relation between the classical perturbation observer and linear extended state observer is deduced, and the parameter tuning problem of the third-order ESO is transformed into the design problem of a low-pass filter. Then a Chebyshev filter is employed to improve the performance of the ESO. The simulation results show that, compared with the existing parameter tuning method, the proposed method endows the ESO with better noise suppression ability and disturbance observation performance.