This paper analyzes the dynamic behavior of chaotic oscillation of a second-order power system model, including the analysis of time domain waveforms and phase diagrams. In order to control the chaotic oscillation in power system, an adaptive total sliding mode controller is designed by combining total sliding mode control with adaptive control. The designed controller overcomes the shortcoming of the sliding mode control that need to know the upper bound of the disturbance, while retaining the advantage that the sliding mode control has good robustness. Two different adaptive laws are used to estimate the disturbance of the system, and the control effects of the two different adaptive rates are compared. The simulation results demonstrate the effectiveness and good robustness of the controller. This work is supported by Natural Science Foundation of Shandong Province (No. ZR2016EEM13).