Motion analysis and experiment of clod cleaning effect were conducted on clod cleaner of 4HLB—2 type peanut combine harvester. Linear velocity and angular velocity of flap plate varied with time according to sinusoidal law. During one clod cleaning cycle, two flapping processes were completed, and the most intense flapping status appeared twice. Clod cleaning effect of the second half of the flapping path was better than that of the first half. The flapping strength of the plates decreased from the ends to the middle, and some of the middle path was viewed as invalid section. Clod cleaning experiment showed that clod cleaning rate was mainly affected by flapping times taken by peanut clusters, and dropped peanut loss was mainly determined by angle amplitude of the flap plates. Higher vibration frequency and smaller angel amplitude were preferred during field working. 