The invention is suitable for the technical field of computer communication and provides a method and a system for transmitting voice messages. The method comprises the following steps: receiving the voice data collected by a first talkback terminal; cyclically detecting whether the size of the acquired voice data reaches a preset threshold value; and when the size of the collected voice data reaches the preset threshold value, or when the size of the collected voice data does not reach the preset threshold value but contains a voice message terminating symbol, uploading the collected voice data to a transfer server through a preset network so as to realize asynchronous implementation of collection and uploading. The method and the system provided by the invention solve the problem that an effective talkback data transmission method cannot be provided in the prior art, causing delayed talkback data transmission time, and reduces talkback delay and improves the user experience at the talkback terminals through the asynchronous implementation of collection and uploading of the voice data.