Abstract: To further investigate the operation mechanism and improve the cutting quality of the root profiling floating cutting mechanism, the kinematic characteristics of the profiling floating operation process of the cutting mechanism were analyzed in this paper. Mathematical model of the floating displacement of the cutting mechanism, rotary cutter blade’s trajectory surface, and cutter blade’s cutting speed were measured. The influences of the structure and kinematic parameters of the root-cutting mechanism on profiling floating cutting were explored. Simultaneously, the cutter motion trajectory curve, time-cutting speed curve, and displacement-cutting speed curve were obtained using the ADAMS virtual prototype simulation test. Also, the influences of cutter rotational speed, cutter quantity, cutter blade position and displacement on cutting times, missed cutting area, cutter motion trajectory, and cutting speed were analyzed. The research results show that by setting the structure and kinematic parameters of the root cutting mechanism reasonably, the profiling floating cutting operation of the machine can be effectively realized, and the root cutting operation effect can be improved. When the conveying speed was 1 m/s, the cutter angle was 33°, and the rotational speed of the cutter was 2 600 r/min. The number of root cuts could reach 2 times by the rotated highest point of single cutting edge, and the missing cutting area was minimal. When the conveying speed was 1 m/s, the cutter angle was 33°, the rotational speed of the cutter was 1 000 r/min, and the cutter quantity was 4 pieces. The number of root cuts could reach 2 times by the rotated highest point of all cutting edges, and the missing cutting area was minimal. This study can serve as a theoretical foundation for future research on the operation mechanism and mechanism optimization of the root profiling floating cutting mechanism of garlic combined harvester.