Objective To study the best formulation and technology of quercetin-loaded polylactic-co-glycolic acid-D-α-tocopheryl polyethylene glycol 1000 succinate(PLGA-TPGS) nanoparticles(QPTN) with QT as model drug and PLGA-TPGS as polymer materials by orthogonal tests,and to investigate the in vitro stability of QPTN. Methods To ensure the best formula-tion and technology for preparing QPTN,single-factor test was established to determine the influence of the ratio of quercetin to PLGA-TPGS,the concentration of TPGS as emulsifiers,the ultrasonic power and ultrasonic time to the particle size,drug loading (DL) and entrapment efficiency(EE).According to single-factor test,the factor levels of nanoparticles were set to select the best prescription and technology of QPTN by orthogonal test.The stability of QPTN was examined using the effecting factor test,accel-eration test and long-term test. Results The best formulation and technology of QPTN was that the ratio of quercetin to PLGA-TPGS was 3:10 (W:W) with 0.05% TPGS as emulsifier,the mixed solution was sonicated for 6 min at 200 W.The average particle size,DL and EE of QPTN prepared under the conditions described above were (155.4 ± 2.7) nm,(21.6 ± 1.5)% and (93.7±2.9)% (n=6),respectively.In the in vitro stability test,QPTN showed a good stability at high temperature,high humidity and strong light condition. Conclusion The best formulation and preparation technology of QPTN was selected.QPTN got small particle size,high DL and EE,and good in vitro stability.