Motion of a pinching belt transfer system used in automated post classification machines or automated ticket gates is simulated by a FEM soft ware and velocity characteristics of belts and a transferred medium against a belt-roller lift are investigated. The treated system is composed of two sets of a belt-roller system, which has two rollers and a belt. The results show that the velocity of the drive (driven) side belt does not change (changes largely and approaches a certain value) as the lift increases. The velocity of the driven side belt largely depends on its radius wrapping around the specific roller. The velocity of the medium is close to the mean velocity of the two belts.