A power sharing method for use in communication systems of at least two modes sharing a same power amplifier, said method comprises: determining whether to perform power sharing among communication systems of at least two modes, according to a power demand of a communication system of at least one mode among the communication systems of at least two modes sharing a same power amplifier; and adjusting an available power of communication systems of one or more modes in situation of power sharing among the communication systems of at least two modes to be performed; wherein the step of determining whether to perform power sharing among the communication systems of at least two modes sharing a same power amplifier, according to a power demand of the communication system of at least one mode among communication systems of at least two modes, comprises: obtaining a sharable remaining power of a communication system of a first mode, according to a power demand of said communication system of the first mode and an available power of said communication system of the first mode; deciding whether to agree to receive the sharable remaining power of the communication system of the first mode, according to a power demand of communication systems of one or more other modes; and determining to perform power sharing among the communication systems of at least two modes, when the sharable remaining power of said communication system of the first mode satisfies a preset sharing condition and said communication systems of one or more other modes agree to receive the sharable remaining power of said communication system of the first mode; and wherein the step of deciding whether to agree to receive the sharable remaining power of the communication system of the first mode according to a power demand of communication systems of one or more other modes, comprises: deciding whether to agree to receive the sharable remaining power of the communication system of the first mode, according to network load of the communication systems of one or more other modes or a remaining time during which said remaining power can be shared. determining whether to perform power sharing among communication systems of at least two modes, according to a power demand of a communication system of at least one mode among the communication systems of at least two modes sharing a same power amplifier; and adjusting an available power of communication systems of one or more modes in situation of power sharing among the communication systems of at least two modes to be performed; obtaining a sharable remaining power of a communication system of a first mode, according to a power demand of said communication system of the first mode and an available power of said communication system of the first mode; deciding whether to agree to receive the sharable remaining power of the communication system of the first mode, according to a power demand of communication systems of one or more other modes; and determining to perform power sharing among the communication systems of at least two modes, when the sharable remaining power of said communication system of the first mode satisfies a preset sharing condition and said communication systems of one or more other modes agree to receive the sharable remaining power of said communication system of the first mode; and wherein the step of deciding whether to agree to receive the sharable remaining power of the communication system of the first mode according to a power demand of communication systems of one or more other modes, comprises: deciding whether to agree to receive the sharable remaining power of the communication system of the first mode, according to network load of the communication systems of one or more other modes or a remaining time during which said remaining power can be shared.