Macroscopic subdivision, microscopic subdivision and boundary misorientation angle of cold drawn Ag single crystal with <110> parallel to axis direction have been investigated by EBSD and TEM systematically in the present paper. The results show that with strain increasing, the macroscopic subdivision of cold drawn Ag single crystal becomes severe, the number of deformation band increases, and the width and spacing of deformation bands decrease. When the strains are higher than 0.94, the fiber microstructure parallel to the aixs direction of wires forms gradually as the strains increase. Contrasting to the alloys with the SFE approximate to Ag, the suppression of cross-slip and climb decreases in cold drawn Ag single crystal. Except for the deformation twins, there are abundant of incidental dislocation boundaries and geometry necessary dislocation boundaries in the drawn Ag. The results of boundary misorientation angle show that dislocation slip is the dominate deformation mechanism at low strains. At the medium strains, dislocation slip and twinning compete with each other. At high strains, twinning becomes predominate deformation mechanism.