Through the experimental analysis of hydration process, the flow property of fresh concrete and the mechanical property of hardened concrete, the improving workability and compressive strength of concrete mixed with nano bubble water（NBW） were studied, and its mechanism of action was explored. Experimental research shows that NBW does not significantly improve the flow ability and compressive strength of concrete of grade below C25.However, when compressive strength is over C30, NBW can significantly enhance the flow ability of fresh concrete, and the slump loss over time is obviously reduced. In addition, the compressive strength of hardened concrete at 7, 28d has increased at some extent. The mechanism of the test results is that the NBW plays role of ball lubrication in aggregate slurry surface of fresh concrete, and enhances the flow stability between the coarse and fine layer and, furthermore, improves the workability of fresh concrete. In addition, high potential ζ on the surface of single bubble has high ability of adsorption and increases ion seeding quantities in the solution and increases the effective cement hydration product.