The invention provides a network seamless covering method and system based on fast access of an 802.11 wireless terminal. The method includes the steps that a fixed AP is set in the position of a pre-access network based on the 802.11 wireless terminal; a multi-user antenna set for receiving signals transmitted based on the 802.11 wireless terminal, shielding interference signals, lowering electromagnetic noise and increasing the system throughput is arranged on the fixed AP; the fixed AP has access to a Mesh network through an MP access point in the Mesh network, and information contained in the received signals is transmitted to the Mesh network to be transmitted. By the adoption of the method and system, in a severe signal-to-noise-ratio environment, communication quality and communication efficiency are improved, the node coverage range is increased, communication blind districts are effectively reduced, the fixed AP is compatible in the Mesh network, a hybrid Mesh network is formed, all terminal equipment can be compatible, seamless coverage is achieved, and the problems that wireless equipment in an existing network is difficult in access, data transmission throughput is low, and network coverage is not complete are solved.