The invention discloses a background service progress unit, a seat system and a calling control method thereof. The background service progress unit comprises a protocol stack module, a state machine module and a service access interface module. The seat system comprises a browser and the background service progress unit. The method comprises the following steps: sending an operation request of acustomer representative to the background service progress unit by the browser through an operation page; judging whether the requested operation can be executed currently or not by the background service progress unit, if so, sending the operation request to a CTI server; transmitting the received operation request to an automatic calling distributor to execute the operation by the CTI server, and after the operation is executed, transmitting a notification message of finishing the operation to the background service progress unit; and switching seat states by the background service progressunit according to the notification message of finishing the operation. The invention ensures that the customer representative can log in the CTI server and treat callings through an ordinary computerhost.