Abstract: Understanding the growth responses of Cyphomandra betacea Sendt. seedlings to varying light conditions is essential for optimizing seedling cultivation strategies. This study investigated the morphological traits, organ-specific biomass allocation, and non-structural carbohydrate (NSC) dynamics in one-year old C. betacea seedlings subjected to four light regimes: full light (CK: 0% shade), light shade (S₁: 25% shade), medium shade (S₂: 50% shade), and heavy shade (S₃: 70% shade). Results showed significant differences in seedling height and soluble sugar and starch concentrations in the roots and leaves across treatments (P<0.05). As shading intensity increased, seedling height, ground diameter, and leaf starch content initially declined and then increased, while organ biomass followed the order: root> leaf>stem. Soluble sugar and starch levels in stems exhibited an opposite trend. A significant positive correlation was detected between stem soluble sugar concentration and root biomass (P<0.05). Fuzzy synthesis indicated that 50% shade was the optimal condition for seedling performance. These findings indicate that C. betacea seedlings exhibit moderate shade tolerance, and 50% shade may enhance seedling development.