Abstract: ATo evaluate the meltspinning spinnability of cellulose diacetategraftpoly(lactic acid) copolymer(CDA-g-PLA), the rheological behaviors of CDAgPLA were investigated by means of rheograph 25 rheometer. Results showed that CDAgPLA was a typical pseudo plastic fluid that exhibiting shear thinning phenomena. The nonNewtonian index (n), apparent viscosity(ηa) decreased, but the viscous coefficient(K), structure viscosity index(Δη), viscous activation energy (Eη) of the CDAgPLA melts increased with the increasing of the lactyl sidechains of CDAgPLA. The nonNewtonian index increased, but the viscous coefficient and apparent viscosity decreased with the increasing of the temperature. The best meltspinning processing temperature for CDAgPLA copolymer should be controlled in 170-180°C.