The invention relates to a flow control device of IP load bearing and a method thereof; wherein, the device comprises a call control module, a memory module and a flow control module; the method comprises the following steps: the call control module counts the accessing call on the IP load bearing and stores the accessing call in the memory module; the flow control module gives off test call to the IP load bearing, obtains service quality parameters and obtains a congestion rank; according to the current congestion rank, the amount of the calls which are admitted to access is adjusted and after adjustment, the amount of the calls which are admitted to access is written in the memory module; if new call requirements appear, the call control module makes a judgment of whether the accessed call amount reaches the admitted accessing call amount recorded in the memory module; if the accessed call amount reaches the admitted accessing call amount recorded in the memory module, new calls are rejected; if the accessed call amount does not reach the admitted accessing call amount recorded in the memory module, the new calls are admitted. The invention makes a dynamic regulation of the admitted accessing call amount on the IP transmission according to the current congestion situation of the network, thereby ensuring the quality of conversation of users and improving the comfortable felling of the users.