<p>Home furnishings made from conventional petroleum-based plastics are unsustainable. Polylactic acid (PLA) is an important bio-based biodegradable material that can replace petroleum-based plastics. To improve the mechanical properties of PLA, composites are prepared by melt-blending plant powder and eco-friendly plasticizer with PLA, and the materials are then treated under isothermal conditions. When turmeric powder (TP) is added at 3 wt% and castor oil (CO) at 15 wt%, the elongation at break of CO₁₅/TP₃/PLA composites reaches 30% after two days of isothermal treatment, which is 6 times that of pure PLA and 3.3 times that of composites without isothermal treatment. There are interactions among components in the composites, and the isothermal treatment greatly increases mobility of polymer chains. Using the CO₁₅/TP₃/PLA composites as one of materials, a sustainable vase is produced by combining traditional weaving with modern 3D printing. This work has made a breakthrough in the research on the influence of isothermal treatment on the mechanical properties of PLA composites and in the design of artistic works, which realized the convergence of eco-friendly materials, traditional craftsmanship, and artistic design, and provided a reference for the use of bio-based biodegradable materials in sustainable home furnishings.</p>