Abstract: The high quality graphemes in larger size with few layers were synthesized from natural flake graphite by hydrothermal and ultrasonic method. The microstructure, thermal stability and electric conductivity of the obtained graphenes were characterized by laser Raman spectra (Raman), transmission electron microscopy (TEM), atomic force microscopy (AFM), thermo-gravimetric analysis (TG) and four probe teaster. The results show that the prepared graphenses were mostly double layers in the micron size range, and the spacing between layers was about 2 nm. The electric conductivity was about 808.06 S·cm-1 at room temperature.