Abstract: OBJECTIVE To investigate the enhancement of oral bioavailability of curcumin loaded PLGA nanoparticles. METHODS Curcumin loaded PLGA nanoparticle was developed by a emulsion method, and then characterized by a DLS, TEM and zeta potential. In vitro release study and in vitro stability test were also examined. The oral bioavailability study of curcumin and curcumin loaded PLGA nanoparticles was performed after the oral administration. RESULTS Curcumin loaded PLGA nanoparticles had mean diameter of 200 nm with uniform size distribution. And the developed nanoparticles with improvement of stability of curcumin had high drug encapsulation efficiency and drug loading capacity. In vitro release study showed that curcumin was sustained release from nanoparticles. After 30 min of oral administration of curcumin or curcumin loaded PLGA nanoparticles (100 mg·kg^-1), the blood concentration of curcumin loaded PLGA nanoparticles group showed great significance with that of curcumin group. The bioavailability of curcumin was enhanced 5.2-fold in curcumin loaded PLGA nanoparticles groups as compared with curcumin group. CONCLUSION Curcumin loaded PLGA nanoparticles could greatly improve the stability of curcumin and oral bioavailability of curcumin.