An excellent design of the damper is inseparable from an accurate acquisition of motion amplitude and frequency values of transmission lines. However, these values, in general, are remarkably difficult to precisely measure due to the harsh measurement environments and complex motions of transmission lines. To solve these problems, a motion-characteristic-analysis-method-based inertial measurement, by employing a three-axis accelerometer and a three-axis gyroscope, is designed to recognize the motion state and estimate the motion amplitude and frequency of transmission lines. The center of the inertial measurement method lies in motion signal extraction involving frequency slice wavelet transform and weighted singular value decomposition. Experimental results show that the proposed method adapts well to the motion characteristic analysis of transmission lines.