The present disclosure discloses a method for mapping a logical channel to a Media Access Control (MAC) flow, the method includes: a Radio Network Controller (RNC) informs a User Equipment (UE) of corresponding relationship between a Common Control Channel (CCCH) and an Enhanced-Dedicated Channel (E-DCH) MAC flow through signaling; the UE receives the signaling, and obtains the corresponding relationship between the CCCH and the E-DCH MAC flow. The present disclosure further discloses a system for mapping a logical channel to an MAC flow. Through the method and system disclosed in the present disclosure, it is convenient for both a Node B (NodeB) and UE can accurately obtain the corresponding relationship between the CCCH and the E-DCH MAC flow, which ensures the NodeB decodes correctly, thus improving the success rate in receiving signaling and data.