In order to realize the axial strain measurement,an axial strain measurement sys tem based on curvature fiber optic sensor is established and its algorithms,such as the layou t of the sensor,and the position optimization of sensitive zone,and the mathemat ical model of measuring system are investigated.Firstly, based on the characteristic that the curvature fiber optic sensor is only sensit ive to the curvature changing,the curvature fiber optic sensor including a circular arc is arranged on the surface of object and make sure that the sensitive zone is perpendicular to the surface of object.The moving paths of po ints on fiber optic sensor under axial loading are analyzed and the mathematical model is set up between axial st rain and curvature changing of fiber optic sensor.Then,based on the above mathematical model,the position op timization of sensitive zone is done.Finally,polyurethane rubber block is compressed on electronic all-powerf ul experiment machine and makes it undergo an axial deformation.The proposed measuring system is used to measur e the axial strain of polyurethane rubber block.Experimental results indicate that the maximum strain deviation is 0.0028,which shows the validity of the measuri ng system.