Service products have the characteristics such as non inventory and so on and require service supply chain structure with stronger self organizing ability, thus, a general dynamic reconstruction model adapting to the environment needs to be found and fractal supply chain has the characteristics such as self similarity, self organization, self optimization and the like and can balance the stability and flexibility of supply chain organization structure. Based on fractal theory, service supply chain is decomposed into a lot of fractal supply chain cells, the calculation model on the similarity between fractal supply chain cells is constructed and servicesupply chain network organization structure can be accurately studied. The analysis of simulation examples on port service supply chain shows that the calculated results of self-similarity dimension can better study present complex service supply chain networks.