The influence surface of the spatial structure is difficult to be calculated by the existing two-dimensional boundary element method. Therefore, a damage localization method based on deflection influence surfaces (DIS) calculated by the boundary face method (BFM) is proposed. A BFM program with a built-in cycle is written. Through this program, the internal forces and deformations of a square plate and simply supported T-beam structures are calculated using the static equilibrium method. The domain of the order of the bivariate polynomial function (BPF) is specified; a quadratic optimization influence surface program is established; the minimum mean square error DIS is obtained. The BFM results are compared with the analytical solution results, and these errors do not exceed 1.8‰. Therefore, the accuracy and effectiveness of calculating DIS using the BFM method are verified. Damage localization is studied based on the obtained high-precision DIS and verified through a simply supported T-beam experiment. The proposed method is compared with the traditional DIS damage localization method. Under single and double damage conditions, the damage location accuracy of the proposed method is improved by 28.6% and 16.7% respectively.