This paper presents a theoretical analysis of dynamic process of plastic thin spherical shell under local impact. Firstly, the deformation mode of spherical shell was given by introducing isometric transformation of surface bending. Secondly, on the basis of introducing the yield conditions of weak interaction, the governing equation of motion of the rigid-plastic spherical shell was given by energy balance. Thirdly, the governing equations were solved by the method of Runge-Kutta. Fourthly, by adopting the numerical method, the deformation of the spherical shell under local impact was investigated and the deformation mode was obtained. Finally, a comparison made between theoretical, numerical results and the experimental ones indicated that the three groups of results were in better conformity with each other. The present results of the deformation of the spherical shell used in this paper are reasonable and can be used to predict the degree of damage of a spherical shell under local impact for engineering application.