Provided is a mail sorting system including: a detection unit configured to output a detection signal for a length of a mail inserted to a conveyor belt; a crossbelt driving unit configured to control a motor interworking with a crossbelt including a central region and first and second lateral regions adjacent to both sides based on the central region where the mail is moved and arranged from the conveyor belt; and a control unit configured to transmit a motor control signal which controls at least one of an rpm and a rotational speed of the motor so that the mail is arranged on any one of the central region and the first and second lateral regions based on the detection signal, to the crossbelt driving unit, in order to easily discharge the mail from a destination discharge point by disposing the inserted mail at a setting region of the crossbelt.