This paper puts forward the calculating model of Single point Mooring (SPM) anticollision ring, analyzes the deformation and internal forces of the outer edge between two spokes by means of curved beam theory, therefore gets the theoretical solution of the anticollision ring by boundary and continuous conditions. Finally, the paper takes the SPM anticollision ring of wei 10—3 field in South China Sea as an example, analyzes in detail the changing relations of the internal forces and deformation of anticollision ring with pre一tighting forces of the spokes.The results show that spoke fracturing accidents of the SPM anticollision ring of wei 10一3 field results from the unreasonable pre一tighting force of the spokes.