A method of flow control between radio network controller and base station is disclosed. The method includes: step 1, the base station carrying information of Maximum PDU Length in a capacity allocation frame of High Speed Downlink Shared Channel; step 2, the radio network controller receiving the capacity allocation frame from the base station; step 3, the radio network controller transmitting data to the base station, wherein the amount of data transmitted during one HS-DSCH Interval is less than or equal to the product of Maximum PDU Length carried in said capacity allocation frame and the maximum number of PDUs that can be transmitted during one HS-DSCH Interval. The disclosed method enables the base station control the flow with the radio network controller in the common state of the fortified connection mode.