Facing the global consensus to lift the ecological crisis and poverty eradication, the challenge toward a more sustainable fashion business has become an important issue within the professional field. Although there are several social forces and common effort driving the progress toward sustainability, the overall accomplishment of the fashion industry still has limited results. The main reason is the outstanding performance of the global fashion system and contemporary society's obsession with fast fashion consumption. This article first sorts out the relevant theories supporting sustainable fashion development from existing literature, and then collects the results of companies' real achievement of sustainable practice changes. After comparing theories and practices, we find out the gap between the two and the reasons behind It. This contribution could provide path to fill the disparity in theory and practice.