Considering the refractive index change of bending fiber relative to straight fiber due to internal stress of bending fiber,bending loss model of mono-mode fiber was modified. On the basis of modification,the three results were compared,i. e.,experimental data obtained by other authors,corrected and uncorrected theoretical results. The result shows that the corrected results accord with experimental data well. It will provide as an important reference for analyzing transmission characteristics of light in strong bending mono-mode fibers.