A method, apparatus, and system are provided for controlling data transmission in the field of voice communication. In the method: a server device receives a blocking request sent by a first terminal corresponding to a first user in a user group, where the blocking request carries an ID of a second user in the user group. The server device receives the voice data sent by a second terminal corresponding to the second user who is identified by the ID in the blocking request, and transmitting the voice data to terminals corresponding to other users in the user group apart from the first user and the second user. The voice data sent by any terminal corresponding to the second user is transmitted to the terminals corresponding to other users apart from the first user and the second user after receiving the blocking request carrying the ID of the second user.