The invention provides a sensor for measuring the relative slippage between interfaces based on the EFPI principles. The sensor can comprise two optical fibers and two inclined planes disposed on a reflection inclined plane. The surface of each inclined surface is provided with a reflection plane, and the bottoms of the optical fibers are provided with reflection end faces. Moreover, the reflection planes are perpendicular to the optical axis of one optical fiber, thereby forming a Fabry-Perot cavity between the reflection end faces and an emission plane. At this moment, the slippage of an object B relative to an object B in a plane can be measured. Also, one optical fiber and one inclined surface can be added, so the slippage of the object B relative to the object A in a three-dimensional space can be measured. The sensor is not affected by temperature and electromagnetic factors, is high in precision, and is high in anti-interference and durability performances. The sensor is good in application prospect, is especially suitable for the high-precision measurement of the slippage and environment temperature under the action of structure static force and power or long-time load, and can judge the safety degree of a structure.