The structural strain and deformation are functionally related quantit ies and the latter can usually be inferred from the former.However,the strain is very small for a thi n structure with a small deformation, so it is very hard to be detected.A light intensity modulation fiber-opti c sensor,which can measure deformation directly,is developed.A light leakage zone is introduced to increase the sensitivity of the fiber to deformation.Cantilevered beam,simple support beam and cylinders are used to an alyze the static characteristics,and the static curve of the sensor is obtained .The sensitive directionality of the sensor is also measured and analyzed.The results show that the sensor can distinguish the direction of defo rmation and the output of sensor is linear with deformation curvature in the range from －16.67m－1 to 16.67m－1 (the corresponding radius is larger than 60mm).The Monte Carlo simulation by ray tracing and an orthogonal matrix are us ed to optimize the fiber-optic sensor′s configuration.The simulation results show that the depth of the light leakage zone and the number of teeth are two main parameters that affect the sensor′s sensitivity,which can provide a scientific evidence for better performance of the sensors.