Abstract: In order to evaluate the dynamic characteristics of a large-scale CNC gantry guideway grinding machine, a combination of simulation analysis and experimental testing was conducted to investigate the natural frequency and mode characteristics. Firstly, a finite element simulation model was established to analyze the vibration characteristics and weak points of the designed machine tool. Then a multi-point hammering excitation method was adopted to acquire the natural frequency and damping ratio of the machine tool. The finite element analysis results indicate that the column, crossbeam, and vertical carriage motion components are prone to vibration deformation in the preceding six-order modes. The measured preceding six-order natural frequencies of the CNC gantry guideway grinding machine were 49.31, 81.22, 129.48, 143.39, 201.38, and 212.18 Hz, respectively. Compared with the finite element simulation results, the maximum error was 12.39%, the minimum error was 3.54%, and the average absolute error was 7.04%. The paper provides an important reference for the simulation analysis and experimental testing of the dynamic characteristics of a large-scale CNC gantry guideway grinding machine.