When optical fiber is deployed in practical engineering, bending and stretching of fiber optics is inevitable, which will affect optical communication. The fiber losses of different bending radii are simulated by COMSOL software. In order to verify the accuracy of simulation results, an experiment was designed to measure the losses of single-mode fiber under different bending radii and tension forces. The results show that the sensitive bending diameter of fiber loss is between 5 mm and 10 mm. The tensile effect has little influence on the fiber loss, but when the tensile force is greater than 160 N, the fiber breaks. This study provides an important reference for fiber layout in practical engineering.