A power sharing method for use in communication systems of at least two different modes sharing a same power amplifier, said method comprises: determining whether to perform power sharing among communication systems of the different modes, according to a power demand of a communication system of at least one mode among the communication systems of the different modes sharing a same power amplifier; and adjusting(102;204) an available power of communication systems of one or more modes if it is determined to perform power sharing among the communication systems of the different modes, the step of determining whether to perform power sharing among the communication systems of different modes sharing a same power amplifier, according to a power demand of the communication system of at least one mode among the communication systems of different modes, further comprises: within a preset period, 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 different modes, if 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. determining whether to perform power sharing among communication systems of the different modes, according to a power demand of a communication system of at least one mode among the communication systems of the different modes sharing a same power amplifier; and adjusting(102;204) an available power of communication systems of one or more modes if it is determined to perform power sharing among the communication systems of the different modes, the step of determining whether to perform power sharing among the communication systems of different modes sharing a same power amplifier, according to a power demand of the communication system of at least one mode among the communication systems of different modes, further comprises: within a preset period, 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 different modes, if 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. within a preset period, 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 different modes, if 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.