Electrolytic copper foils with different thicknesses were prepared by adjusting the electrodeposition time and controlling the parameters of other electrolytic processes. Using SEM, XRD, EBSD, and Universal testing machine to research the effects of surface morphology, texture, size effect and fracture mechanism on the tensile properties of electrolytic copper foil with different thicknesses. The results show that with the progress of electrodeposition, the grain size of the surface increases, and the orientation of the crystal plane {220} becomes stronger. When the copper foil thickness is less than 18 μm, the tensile strength and elongation of the ultra-thin copper foils increase with the thickness of the copper foil due to the size effect.However, when the thickness of the copper foil is more than 18 μm, as the thickness of the copper foil increases, the grain size becomes larger and the degree of crystal plane orientation becomes higher, which reduces the tensile strength of the copper foil. Key words: Electrolytic copper foil; texture; mechanical properties; size effect