With new differential and integral theory (seeliterature),we give a definition of differential linear displacement,differential curvilinear displacement,differential plane angular displacement,differential linear displacement vector,and differential angular displacement vector.

Thus the angular displacement measurement system is a key component of the corresponding system.

Based on the engineering geologic section model and rock mass parameter of left bank slope of Longtan Hydropower Station,the influential factors were analyzed with orthogonal analysis of toppling rock slope,the range of dominance of toppling slope,was proposed and the topping condition with displacement vector angle in the same nod of different models were also analyzed.

Through the analysis on deformation property and the basic constitution of different stability evolution stages of the accumulative-formation slope, it is found that the surface displacement vector angles of slope are constituted of whole sliding vector angles compressive displacement vector angle, plastic deformation vector angle and creeping deformation vector angle.

Using the composite equation of the angular displacement vectors of the particle and composite equation of the rotating angular displacement vectors of rigid,this article has defined three-dimensional angular vector and its arithmetic regulation,in the end,the article has set up fundamental theory system of angular vector space.