The invention discloses a data transmission flow control method based on a FC (Fiber Channel), which comprises the steps of: designing a synchronous frame transmission module, wherein the module comprises one synchronous frame sending unit and one synchronous frame receiving unit, the synchronous frame sending unit takes charge of configuring and sending a synchronous frame, the synchronous framereceiving unit takes charge of receiving and parsing the synchronous frame, and sending and receiving of the synchronous frame is independent mutually; and designing a flow control module, wherein themodule comprises one FC bus monitoring unit, one FC bus activation unit and one flow counting unit, the FC bus monitoring unit takes charge of monitoring whether a data frame is sent on a FC bus, theFC bus activation unit takes charge of sending an activation instruction to the FC bus, and the flow counting unit takes charge of carrying out initialization, calculation and recovery of flow. The method disclosed by the invention is applicable to both parties of data transmission on the FC bus, is an innovation for a flow control problem in the conventional FC data transmission process, and canimprove efficiency of data transmission of the FC bus.