Abstract: In order to analyze high vibration problem of boom of high ground clearance sprayer in field excitation，modal characteristics of suspension connecting boom were studied.3D model of boom was established through Inventor，and dynamic modal simulation analysis of boom model was carried out through ANSYS Workbench.Simulation results showed that when effective mass participation in each vibration direction was above 0.85，the first 60 natural frequencies of boom were below 120 Hz，and main vibration modes focus on oscillating and flipping in vertical direction.Dynamic modal test was carried out on boom using hammering method.Results of simulation analysis and test were compared，it showed that frequency difference of first 10 modes of boom were both less than 7%，and MAC corresponding to vibration modes of each order were also greater than 0.9.It was explored that boom modal simulation model was correct and results were credible，it could provide a basis for boom vibration characteristics and vibration performance analysis.