This paper addresses the problem of cluster control for multi-biomimetic robotic fish. First, the mechanical design and system configuration of the biomimetic robotic fish are briefly introduced. In order to deal with the challenging problem of cluster control, a cluster control system is proposed based on WiFi technology. Specifically, host computer can transmit wireless signals (IEEE 802.11 signal) to surrounding space as access point (AP), while multi-biomimetic robotic fish can connect to the wireless local area network as station (STA). Then multiple transmission control protocol (TCP) connections can be established with host computer as TCP client and multi-biomimetic robotic fish as TCP server. In this way, host computer can control the multi-biomimetic robotic fish cluster simultaneously. In the end, experimental results demonstrate the feasibility and effectiveness of the designed cluster control system.