Abstract: Harmonic response of the main frame of carrot sowing machine based on seed tape planting method affects overall working quality. Therefore, combined with the agronomic requirements of carrot seeding and the characteristics of seed tape planting method, it is necessary to optimize the main frame structure and ensure the working quality. There are 6 parts of the main frame structure that may directly affect the working performance. These include the position contacting with installation structure of drop irrigation belt, support shaft of installation structure of seed tape, surface above the trench opener of laying structure of drop irrigation belt, exit position of seed tape, handrail, and position contacting with pin roll of structure of tidying up the ridge. The working state of the 6 parts was analyzed using Ansys Workbench 19.2. Through modal analysis, the natural frequencies and modes of the first 6 modes of the main frame structure were obtained. Further, through harmonic response analysis, amplitude response of different frequency to the 6 parts were obtained. Simulation results showed that at 2 500 r/min working speed of single cylinder machine, the amplitudes of x-axis, y-axis and z-axis at the 6 parts were 0.006 mm, 0.002 mm, 0.013 mm; 0.008 mm, 0.01 mm, 0.012 mm; 0.004 mm, 0.003 mm, 0.003 mm; 0.004 mm, 0.005 mm, 0.017 mm; 0.007 mm, 0.017 mm, 0.008 mm; and 0.003 mm, 0.107 mm, 0.036 mm, respectively. It was observed that the designed main frame had no influence on the embedding process of seed tape and the working state of the main frame structure was stable. The main frame provided a stable fixed connection working platform for other execution components. Harmonic response analysis of the main frame provided a theoretical basis for better protecting seed tape, ensuring operation quality and operation stability, obtaining working conditions of the main frame, and further optimizing working environment of the main frame.