Embodiments of the present disclosure disclose a Clos network load balancing method and apparatus. In certain embodiments, the method includes receiving, by a first switch, a first packet and determining, by the first switch, a third switch. The third switch is a switch in a second group of switches. The method includes performing, by the first switch, tunnel encapsulation on the first packet, a destination Internet Protocol (IP) address in a tunnel-encapsulated IP header being an IP address of a second switch. The method includes performing, by the first switch, Internet Protocol in Internet Protocol (IP-in-IP) encapsulation on the tunnel-encapsulated first packet and sending, by the first switch, the IP-in-IP encapsulated first packet.