A method for processing packets of a VLAN in a network switch is provided. The VLAN comprises a plurality of physical LANs and are divided into a plurality of subnets. The method comprises the steps of: receiving a packet through an ingress port of the network switch, wherein the packet is tagged with a VID of the VLAN; finding a VLAN member according to the VID, wherein the VLAN member represents all ports of the network switch dedicated to serving packets of the VLAN; finding a forwarding scope according to the ingress port, wherein the ingress port is one of the ports dedicated to serving packets of a first subnet of the VLAN and the forwarding scope represents all ports of the network switch dedicated to serving packets of the first subnet; and determining an egress port of the packet according to both the VLAN member and the forwarding scope.