In order to enhance the transdermal penetration of CoQ10-loaded nanostructured lipid carriers (CoQ10-NLC), penetration enhancer--quaternized chitosan (QCS) was used to modify the surface of CoQ10-NLC. The self-aggregation behavior of QCS molecular chain was also studied to illuminate the formation mechanism of QCS-CoQ10-NLC. And QCS-CoQ10-NLC with particle size around 500 nm were prepared. In addition, the transdermal penetration of QCS-CoQ10-NLC was investigated by in-vitro transdermal study, the result showed that lipid carriers modified by QCS at 0.5% (w/w) could obviously improve the transdermal penetration of CoQ10 in the skin.