Disclosed herein is a network-based robot control system. The network-based robot control system includes robot terminals, communication modules, and a service server. The service server receives sensing values from sensors of each of the robot terminals through each of the communication modules, generates downstream packets so that synchronous motion control data, voice data or image data is included in a single packet, and transmits the downstream packets to the robot terminal through the communication module. The robot terminal receives the transmitted downstream packets, sequentially stores the downstream packets in a downstream buffer, reads the downstream packets stored in the downstream buffer, and performs a motion or plays voice or images according to the read downstream packets.