The embodiment of the invention discloses a method for data transmission during cell switching, comprising the following steps: when network side equipment determines that UE (user equipment) needs to be switched to a target cell, the network side equipment sends a physical channel reconfiguration massage to the UE, wherein the physical channel reconfiguration massage carries MAC (media access control) entity activation time delay information of the target cell; and the UE sends data to the target cell according to the MAC entity activation time delay information of the target cell. In the embodiment of the invention, when the network side equipment sends the physical channel reconfiguration massage to the UE, the MAC entity activation time delay information of the target cell is sent to the UE, so that the UE can send the data to the target cell after reaching the MAC entity activation time delay of the target cell, and uplink data is not lost thereby lowering the drop call rate in the switching process.