The periodical electrochemical oscillations (especially differential capacitance and conductance oscillations) of nickel electrode can be obviously modified by Triton X-100 in HNO3/H2O system. Triton X-100 concentration affects the behaviors and parameters of the oscillations. A modifying mechanism of the oscillations is proposed in which the adsorption and desorption of Triton X-100 on the electrode play a key role in the oscillations.