Abstract: This paper applies the theory of finite strain to the study of Paleozoic structures in Chengdao region.A displacement function is established by resolving the straining processes based on the analysis of the basic tectonic features and their evolution.The E-W,N-S and vertical components of the displacement vectors of points on the bottom surface of the Paleozoic are calculated so as to give a quantitative description of the deformations.The correlation between the displacement components and the periods of tectonic activities is analyzed.