A method for controlling a timer on buffer status report (BSR) is provided in the present invention, and the method is applied to implement the control of the timer on BSR the system to which Carrier Aggregation technology is applied. Said method includes: starting a retransmission BSR timer (retxBSR-Timer) and a BSR periodic reporting timer (periodicBSR-Timer) when a sub frame has a component carrier which has a BSR to be transmitted; restarting the retxBSR-Timer when a sub frame has a component carrier which has new data transmission resources; and restarting the periodicBSR-Timer when a sub frame has a component carrier which has a long BSR or a short BSR to be transmitted. A device for implementing said method is also provided in the present invention.