CMC /Tb nano-particles were synthesized in different reaction times. Then,the morphology, structure and fluorescence properties of the complexes were investigated by means of SEM, FT-IR and XPS and by using UVVis spectra and PL spectra. The results show that (1) CMC /Tb nano-particles are spherical particles and the particle sizes are around 100 nm; (2) for different reaction times, Tb³⁺ ions bind CMC in a similar way, specifically, all the Tb³⁺ ions react with the atom O of —OH, —COO and —COC groups on CMC chain; (3) however, the coordination structures of CMC /Tb nano-particles are different due to the dynamic equilibrium of CMC conformation during the reaction; (4) CMC acts as the primary light energy absorber and it can effectively sensitize Tb³⁺ ions to make the CMC /Tb nano-particles exhibit four characteristic narrow emission bands, namely, ⁵D₄→⁷F₆ ( 489 nm) , ⁵D₄→⁷F₅ ( 545 nm) , ⁵D₄→⁷F₄ ( 584 nm) and ⁵D₄→⁷F₃ ( 619 nm) ; and ( 5) in the four emission bands,the ⁵D₄→⁷F₅ transition with the green emission is the most prominent band of the Tb³⁺ ions, moreover, its half-peak width is less than 10 nm, and its intensity fluctuates with the reaction time and becomes steady after 75 minutes.