Small world network is one of the most important properties of complex networks, which has the characterists of small average path length and maximum cluster coefficient. Introduce theory of small world into wireless sensor networks is very important to analysises the topology of WSNs(wireless sensor networks), find the hidden rule of WSNs, improve network performance, can be widely used in intelligent transportation, military. This paper reviews the background, the motivation, the state of arts as well as the main issues of existing works related to WSNs based on the model of small world network, tries to draw a comprehensive and clear outline for the studies of small world in WSNs. This work is hopefully beneficial to the researchers of complex network, WSNs and others relative domains.