Abstract: The field investigations of the Minxian-Zhangxian Earthquake (MZE) indicated that amplification effects of site conditions and topography on ground motion were very obvious in loess regions. There is a common question why the small peak ground acceleration (PGA) did cause relatively serious damage of loess area in MZE. Based on the strong motion records of the MZE, this paper analyzes the amplitude, spectrum and duration characteristics of ground motion, discusses the influence of propagation distance and site conditions on the characteristic parameters of ground motion. From the perspective of ground motion characteristics, the reasons for the relatively heavy earthquake damage and the potential impact on the earthquake damage are analyzed. The results show that: 1) Compared with Class I site, the PGA of Class III site is increased by 2.1~4.6 times, the duration is prolonged by 10~43s, and the response spectrum value is larger in the period of 0.18~0.86s. 2) Compared with non-loess site, the PGA of loess site is increased by 3 times, the peak ground velocity of loess site is increased by 2 times, the duration is prolonged by 8~35s, and the response spectrum value is obviously larger when the period is greater than 0.32s. There is a significant loess site ground motion amplification effect. 3) The pseudo-acceleration spectrum of design earthquake-2^nd group and site-class II significantly larger than Chinese design response spectra in period 0.8~0.3s.