A series of novel tunable luminescence color CMC ( Carboxymethyl Cellulose) -Tb /Eu nano complexes were synthesized via the coprecipitation reaction with microwave-assisted heating.Then,the morphology,structure,fluorescence properties and energy transfer characteristic of the synthesized nano complexes were investigated by means of SEM-EDS,TEM,XPS,UV-Vis,PL spectra and decay lifetime.The results show that ( 1) as compared with CMC,there exist more cracks on the surface of the synthesized CMC-Tb /Eu nano complexes; ( 2) in the nano complexes,small solid particles cluster on the surface of CMC,and the average size of the particles is 75 ～ 98 nm; ( 3) the O atoms in —OH,—COO^- and —COC— of the molecular chain of CMC bond with Tb3 + or Eu³⁺ in the synthesized nano complexes ionically and covalently; ( 4) CMC is the main energy acceptor,and in the energy transfer between CMC and Tb or between CMC and Eu,the efficiency of transferring energy from CMC to Tb3 + is higher than that to Eu³⁺ ; ( 5) under a 350 nm excitation,the ⁵D₄→ ⁷F₅ ( 544 nm) and ⁵D₄→ ⁷F₆ ( 489 nm) transitions of Tb³⁺ appear in the emission spectrum of CMC-Tb /Eu; ( 6) the two peaks respectively locating at around 589 nm and 616 nm result from the overlapping of the transitions ( ⁵D₄ →⁷F₃ and ⁵D₄ →⁷F₄ ) of Tb³⁺ and the transitions ( ⁵D₀ →⁷F₁ and ⁵D₀ →⁷F₂ ) of Eu³⁺ ,respectively; and ( 7) the tunable luminescence color is realized.The intensity change of ⁵D₄ →⁷F₅ of Tb³⁺ and the luminescence lifetime change of the synthesize nano complexes demonstrate that the energy transfer of Tb( Ⅲ)→ Eu( Ⅲ) exists in the synthesized nano complexes.