The nano modified concrete was prepared based on coating aggregate with nano SiO2 enhanced technology. The rheological properties of paste, the compressive strength, the mass loss and the relative dynamic modulus of concrete were tested. The microstructure of the interface transition zone and the pore structures were studied by scanning electron microscope（SEM） and mercury porosimeter（MIP）. The results show that the viscosity of the paste is significantly increased and the coated aggregate with nano SiO2 is strengthened The mechanical and frost resistance of the concrete with aggregate coated by nano SiO2 are enhanced, because the strength loss and the quality loss are lower than that of the ordinary nano modified concrete. The interface transition zone becomes denser and the harmful pores are reduced by 101% while the harmless pores are increased by 147%, compared with the ordinary nano modified concrete.