A bridge intelligent cable system with a built-in fiber grating sensor, comprising: an anchor cup, a wire dividing plate, a connecting cylinder, a fiber grating sensor built in the connecting cylinder, and a cable body, wherein the fiber grating sensor comprises a fiber grating strain sensor and a fiber grating temperature sensor, wherein the fiber grating strain sensor and the fiber grating temperature sensor are within a package, tail fibers of the fiber grating strain sensor and the fiber grating temperature sensor extend through the connecting cylinder, the packaged fiber grating strain sensor is fixedly connected to an outer-layer steel wire of the connecting cylinder, the packaged fiber grating temperature sensor is suspended on the steel wire of the connecting cylinder, holes are punched in the wire dividing plate, a steel pipe is buried in the connecting cylinder and the anchor cup, the steel pipe extends through the holes in the wire dividing plate, each of the tail fibers of the fiber grating strain sensor and the fiber grating temperature sensor is connected to a fiber cable, wherein the fiber cable extends through the steel pipe, and the fiber cable extending through the steel pipe is connectable to a fiber grating demodulator; wherein a package structure of the fiber grating strain sensor comprises: the fiber grating strain sensor 9 comprising a first fiber grating, first steel pipes, second steel pipes, a first protection steel pipe, and supports; wherein the number of the first protection steel pipe is one, the number of the first steel pipes is two, the number of the supports is two, and the number of the second steel pipes is two, wherein the two first steel pipes, the two supports, and the two second steel pipes are arranged on two sides of the first protection steel pipe in bilateral symmetry, a diameter of the second steel pipe is less than a diameter of the first steel pipe which is less than a diameter of the first protection steel pipe; a groove is opened axially in the middle of the second steel pipe; a hole is punched in an upper area of the support, wherein the first steel pipe passes through the hole in the upper area of the support and is connected to the support; two ends of the first protection steel pipe are respectively sleeved on one end of the two first steel pipes; the other end of the first steel pipe is sleeved on one end of the second steel pipe, the first fiber grating passes through the second steel pipe, the first steel pipe, and the first protection steel pipe; a grating region is located at a central position of the first protection steel pipe; two ends of the first fiber grating are fixed in the grooves of the two second steel pipes by adhesive; a first heat shrinkable sleeve is sleeved outside a grooved place of the second steel pipe; tail fibers at the two ends of the first fiber grating extend through the other end of the second steel pipe; the support of the fiber grating strain sensor is connected to the steel wire of the connecting cylinder, a protection hood covers on the fiber grating strain sensor for protection, a sealing place of the protection hood and the steel wire is sealed by mastic, and an adhesive tape seals a gap of the steel wire which is sealed by mastic for forming the totally packaged fiber grating strain sensor; and wherein a package structure of the fiber grating temperature sensor comprises: the fiber grating temperature sensor comprising a second fiber grating, a second protection steel pipe, and a second heat shrinkable sleeve, wherein the second fiber grating is suspended in the second protection steel pipe; the second fiber grating is connected to tail fibers from the second protection steel pipe; the tail fibers are fixed by adhesive at a place where they extend from the second protection steel pipe, and the second heat shrinkable sleeve is sleeved on.