In order to solve the problems of difficulty and high cost in installing and maintaining sensors in water injection well, a target type fiber Bragg grating（FBG） flow sensor based on lever-hinge structure is designed and theoretically analyzed. FBG1 and FBG3 in the sensor structure are pasted on the two ends of lever-hinge respectively to form a differential structure, which makes the sensor have the characteristics of low start-up and large range. Temperature compensation grating FBG2 is used to measure the temperature and flow simultaneously. The structure of the sensor is simulated and optimized, and the optimization parameters of the sensor are obtained. Based on these parameters, flow measurement, repeatability, temperature measurement, temperature compensation and stability experiment are carried out. The experimental results show that the sensor can simultaneously measure the fluid flow and temperature, its temperature sensitivity is 17.94 pm/℃ and the flow resolution is 0.039 L/s.