Abstract: North China region (N37.7°~41.7°, E114°~120°) is divided into 24 sections, in which each section has the range of 1°×1° in this paper. Using the multi-station methods we calculated the velocity ratio and correlation coefficients of 21 sections. According to the consequence, there is certain relationship between seismic velocity ratio, rock property, temperature and strain in the two-dimensional distribution. At the same time, we studied the two formulas of multi-station method. Although there is difference in the theoretical deduction, the two formulas have consistent consequence and the trend is both consistent with time. The more accurate data we use, the more consistent the consequence is.

Key words: Average velocity ratio, Multi-station method, North China region