A power sharing method for use in communication systems of at least two different communication modes sharing a same power amplifier, wherein the method comprises: determining whether to perform power sharing among the communication systems of the at least two different communication modes, according to a power demand of a communication system of at least one communication mode among the communication systems of the at least two different communication modes sharing a same power amplifier; and adjusting (102; 204)an available power of communication systems of one or more communication modes in situation of power sharing among the communication systems of the at least two different communication modes to be performed; characterized in that, the step of determining whether to perform power sharing among the communication systems of the at least two different communication modes sharing a same power amplifier, according to a power demand of the communication system of at least one communication mode among communication systems of the at least two different communication modes, comprises: obtaining a sharable remaining power of a communication system of a first communication mode, according to a power demand of said communication system of the first communication mode and an available power of said communication system of the first communication mode; deciding whether to agree to receive the sharable remaining power of the communication system of the first communication mode, according to a power demand of communication systems of one or more other communication modes; and determining to perform power sharing among the communication systems of the at least two different communication modes, if the sharable remaining power of said communication system of the first communication mode satisfies a preset sharing condition and said communication systems of one or more other communication modes agree to receive the sharable remaining power of said communication system of the first communication mode; wherein the at least two different communication modes comprise at least two of the following: global system for mobile communications, universal mobile telecommunications system (UMTS) and long term evolution. determining whether to perform power sharing among the communication systems of the at least two different communication modes, according to a power demand of a communication system of at least one communication mode among the communication systems of the at least two different communication modes sharing a same power amplifier; and adjusting (102; 204)an available power of communication systems of one or more communication modes in situation of power sharing among the communication systems of the at least two different communication modes to be performed; obtaining a sharable remaining power of a communication system of a first communication mode, according to a power demand of said communication system of the first communication mode and an available power of said communication system of the first communication mode; deciding whether to agree to receive the sharable remaining power of the communication system of the first communication mode, according to a power demand of communication systems of one or more other communication modes; and determining to perform power sharing among the communication systems of the at least two different communication modes, if the sharable remaining power of said communication system of the first communication mode satisfies a preset sharing condition and said communication systems of one or more other communication modes agree to receive the sharable remaining power of said communication system of the first communication mode; wherein the at least two different communication modes comprise at least two of the following: global system for mobile communications, universal mobile telecommunications system (UMTS) and long term evolution.