由多式函数、三角函数及其结合逼近桥梁挠度 ,对逼近函数微分求得桥梁挠曲速度和加速度 ,用最小二乘法由桥梁挠度及近似的挠曲速度和加速度识别桥梁的模态位移、模态速度和模态加速度 ,由梁的模态座标方程和最小二乘法识别桥上移动荷载。与以前的识别方法相比 ,函数逼近的识别方法受测量噪声的影响较小。 Bridge deflection is approximated by multi-function, trigonometric functions and their combination. The bridge deflection speed and acceleration are obtained by the differential of approximation function. The bridge mode displacement is identified by the deflection of the bridge and approximate flexural speed and acceleration State velocity and modal acceleration. The moving load on the bridge is identified by the modal coordinate equation of the beam and the least square method. Compared with the previous methods, the recognition of function approximation is less affected by the measurement noise.