Human performance principles, indicators, their metrics and information sharing techniques are applied to nanotech sustainability assessment and risk communication in this paper. The purpose is to optimize the nano-risk performance in sustainable nanotech development. The method takes human physical and cognitive capabilities, limitations into consideration during nanotech sustainability modeling. By integrating the identified human factors into a multi-criteria sustainability assessment model, the proposed method analyzes the nanotech sustainability not only for the conventional Triple Bottom Line effects, but also for human performance improvement. The application of the method to the nanotech sustainability assessment of nano-composite materials is described in the paper.