The present disclosure relates to a method, a device and a system for reducing power consumption of a mobile terminal. The method includes sending a parameter adjustment request to an access network device connected to the mobile terminal in response to an instruction for reducing power consumption; receiving a parameter adjustment instruction sent by the access network device, wherein the parameter adjustment instruction includes a communication parameter to be adjusted, and the communication parameter to be adjusted is a baseband-chip related communication parameter; and adjusting the baseband-chip related communication parameter in the mobile terminal based on the parameter adjustment instruction to reduce the power consumption of the mobile terminal.