High‐strength petroleum‐based materials like plastics have been widely used in various fields, but their nonbiodegradability has caused serious pollution problems. Cellulose, as the most abundant sustainable polymer, has a great chance to act as the ideal substitute for plastics due to its low cost, wide availability, biodegradability, etc. Herein, the recent achievements for developing cellulose “green” solvents and regenerated cellulose materials with high strength via the “bottom‐up” route are presented. Cellulose can be regenerated to produce films/membranes, hydrogels/aerogels, filaments/fibers, microspheres/beads, bioplastics, etc., which show potential applications in textiles, biomedicine, energy storage, packaging, etc. Importantly, these cellulose‐based materials can be biodegraded in soil and oceans, reducing environmental pollution. The cellulose solvents, dissolving mechanism, and strategies for constructing the regenerated cellulose functional materials with high strength and performances, together with the current achievements and urgent challenges are summarized, and some perspectives are also proposed. The near future will be an exciting era for high‐strength biodegradable and renewable materials. The hope is that many environmentally friendly materials with good properties and low cost will be produced for commercial use, which will be beneficial for sustainable development in the world. Rengenerated cellulose materials with the forms of films/membranes, fibers, hydrogels, aerogels, beads/microspheres can be designed via chemical crosslinking, chemically dual‐crosslinking, physical crosslinking, and chemically and physically double crosslinking for achieving the high strength and bidegradability. These cellulose‐based materials are a promising substitute for nonbiodegradable petroleum‐derived synthetic polymers, contribut ing to a sustainable development in the world.