Abstract: With the support of the Baoji City seismic zonation project, a typical loess tableland site is selected and sufficient undisturbed loess samples at different depths (1 m, 3 m, 5 m) collected. Based on the establishment of mathematical function model of seismic subsidence curves, basic parameters have been studied. The initial dynamic stress is affected significantly by and decreases with water content. The critical and ultimate dynamic stress is not sensitive to water content but decreases when it is greater than the plastic limit. The basic parameters show a negative relationship with void ratio, and there exists a critical one; as void ratio is larger than that, the critical and ultimate dynamic stress reduce significantly as void ratio increases. A seismic subsidence indicator, sensitivity coefficient, is proposed to reflect the vulnerability, and the indicator grows with the increase in both water content and void ratio.