针对重大工程领域中需要快速对螺栓预紧力进行监测的需求，根据声弹性原理和胡克定律推导了纵波法预紧力测量公式，搭建了1.25 GHz高采样超声螺栓预紧力测量系统。将频域升采样原理，频域互相关时延估计算法相结合，提出了频域补零互相关时延估计算法；采用仿真的方式验证了互相关时延算法计算结果的稳定性，选取8.8级M30碳钢螺栓，通过标定试验确定其应力系数为1.680 MPa ·ns^-1；再对该型号螺栓进行加载试验，试验结果表明，频域补零互相关算法测试精度可达3.5%，运算速度较传统时域插值算法速度提升约5倍。

In order to meet the demand for rapid monitoring of bolt preload force in major engineering fields, this thesis derives the preload force measurement equation by longitudinal wave method according to the acoustoelasticity principle and Hooke's law, and builds a 1.25 GHz high-sampling ultrasonic bolt preload force measurement system. The frequency domain time-delay estimation algorithm is proposed by combining the frequency domain upsampling principle and the frequency domain interpolation time-delay estimation algorithm; the stability of the calculation results of the interpolation time-delay algorithm is verified by using simulation, and the stress coefficient of 1.680 MPa ·ns^-1 is determined by the calibration test for the selected grade 8.8 M30 carbon steel bolt. then the loading test is conducted for this type of bolt test result show that the frequency domain interpolation time-delay algorithm accuracy can reach 3.5%, the operation speed is about 5 times higher than the traditional time domain interpolation algorithm.