In this paper,two new indices,quasi-acceleration of crustal vertical movement and crustal volume change rate,are presented,which will describe the characteristics of crustal vertical deformation field.The crustal shear deformation,extension deformation,quasi-acceleration and volume change rate are calculated by using releveling data in Hexi area,Gansu since 1970s. The relation between these indices and earthquake risk region judgment is analyzed systematically.The procedure of crustal deformation field evolution in Hexi area is studied.