The embodiment of the invention discloses a sound mixing method, a sound mixing device and a sound mixing system and relates to the technical field of communication. The acoustic fidelity of mixed sound can be ensured and the consumption of a computing resource can be reduced. The method comprises the following steps of receiving audio code stream of each meeting place, and respectively analyzing the audio code stream of each meeting place to obtain sound characteristic values of sound source objects; according to the sequence from large sound characteristic values of the sound source objects to small sound characteristic values of the sound source objects, selecting the sound source objects with preset number as main sound source objects; determining the meeting places where the main sound source objects are; according to the relation between a target meeting place and the meeting places where the main sound source objects are, determining the audio code stream for sound mixing of the target meeting place; performing sound mixing on the audio code stream for sound mixing of the target meeting place, and transmitting the audio code stream which is subjected to sound mixing to the target meeting place; or transmitting the audio code stream for sound mixing of the target meeting place to the target meeting place, and performing sound mixing in the target meeting place. The embodiment of the invention is mainly applied in a sound mixing process.