Seaweed is one of the most important coastal ecosystem-engineers, and the habitat formed by it plays an important role in supporting ecological behaviors (e.g. feeding, growth and recruitment, etc) of marine organisms. However, seaweed beds are declining around the world due to the environmental changes and human activities, which makes non-negligible impact on organisms inhabited there. China suffered severely from this situation. To achieve the goal of sustainable utilization of marine resources, the restoration of seaweed beds is becoming an important assignment of China's ecological environment protection in coastal areas. However, the lack of understanding of ecological function of seaweed and seaweed-formed habitat makes the objectives and methods of the seaweed beds restoration unclear. In this paper, we summarized the ecological function of seaweed and seaweed-formed habitat, such as seaweed beds and seaweed farming area in the context of ecological restoration of seaweed beds. Furthermore, we put forward some thoughts about whether it's suitable for the seaweed farming to be incorporated into the construction of sea ranching. We also suggested some quantitative measures of ecological function in seaweed-formed habitat. Our analysis may provide references for restoring seaweed beds reasonably and efficiently, and sustainable development of seaweed farming industry in the future.