Strain transfer theory of two-way coupled between the Half-plane and the Fiber Bragg Grating sensor was established, the relationship between the measured strain of the surface-bonding Fiber Bragg Grating sensor and the strain of the Half-plane was obtained. The theoretical solution, the Finite Element solution and the experimental date were compared to verify the correctness of the theory, and the relationship between the strain transfer rate and the Young′s modulus of the Half-plane and the half bonding length was analyzed. The result show that the error of the theoretical solution and experimental value is very small, less than 4%, the strain transfer rate increases with the increasing both the Young′s modulus of the Half-plane and the half bonding length, it has some reference value for the design and application of Fiber Bragg Grating sensors.