The plant cell wall is an extremely complicated natural nanoscale structure composed of cellulose microfibrils embedded in a matrix of noncellulosic polysaccharides, further reinforced by the phenolic compound lignins in some cell types. Such a network formed by the interactions of multiscale polymers actually reflects functional form of the cell wall to meet the requirements of plant cell functionalization. Therefore, how plants assemble cell wall functional structure is fundamental in plant biology and critical for crop trait formation and domestication as well. Due to the lack of effective analytical techniques to characterize this fundamental but complex network, it remains difficult to establish direct links between cell-wall genes and phenotypes. The roles of plant cell walls are often underestimated as indirect. Over the past decades, many genes involved in cell wall biosynthesis, modification, and remodeling have been identified. The application of a variety of state-of-the-art techniques has made it possible to reveal the fine cell wall networks and polymer interactions. Hence, many exciting advances in cell wall biology have been achieved in recent years. This review provides an updated overview of the mechanistic and conceptual insights in cell wall functionality, and prospects the opportunities and challenges in this field.