The present invention discloses a data sending method, device and system. The data sending method includes: before establishing a connection with a wireless network side, detecting whether a wireless terminal has data to be sent to the wireless network side, the data to be sent including signaling data for establishing the connection between the wireless terminal and the wireless network side; if a result of detecting whether the wireless terminal has data to be sent to the wireless network side is that the wireless terminal does not have data to be sent, making sure that a power amplifier (PA) of the wireless terminal is in a non-working state; if a result of detecting whether the wireless terminal has data to be sent to the wireless network side is that the wireless terminal has data to be sent, making sure that a PA of the wireless terminal is in a working state.