Nanocatalysis has been the center of nanoscience and nanotechnology, which benefit catalysis in profound ways. Nanostructures and nanopores allow researchers to control the dispersion of active sites, promote desired diffusion pathway of reaction species. Precise size and facet control as well as -assembly of nanoparticles into hierarchical structures lead to new type of catalysts with unprecedented activity and selectivity. Nanosemiconductor materials with various energy level has also broaden our ability to use light and electro field in catalysis for the further applications. Nanocatalysis has become the frontier in chemical synthesis, environmental protection, clean energy, etc. that help us to deal with the exhaust of fossil fuel and global warming.