Abstract: Based on analysis of response spectrum characteristics and microstructure of loess at blasting loess site, the micro-particle-dynamical theory is proposed firstly. According to the particle theory, the dynamic stress-strain-time damping equation is established, then, fluctuation time-history formula of loess seismic response is obtained through applying wave equation. Binding digital data record at the blast site, mechanical parameters of loess are introduced into the fluctuation formula, and the simulation wave curves are acquired. It shows that the waveform and frequency of the calculated acceleration response spectrum and the blasting waveform recording are relatively consistent. Moreover, studied on the characteristics of non-linear spectrum of different loess particles, different causes of formation microstructure of loess has difference response frequency, and correlated to its particle conduction. The loess of loose microstructure particles has more high-frequency components and “longer” power-chain transmission. However, the loess with dense microstructure particles has less high-frequency components and “shorter”power-chain transmission. It provides a new way for theoretical analysis of earthquakes response at loess site.