Reduced graphene oxide membranes with electrical conductivity of 201 S/cm were successfully fabricated by a simple hydriodic acid reducing method. It has been shown that the obtained graphene oxide membranes exhibit a p-type conductive property with a hole carrier concentration of 3.66 x 10(17) cm(-2) and a mobility of 13.7 cm(2)/Vs. The p-type conductive property was mainly attributed to iodine atom adsorption on C atom layer, supported by the energy dispersive X-ray spectrometry and the first-principles calculations based on the density functional theory. The Bader method was used to analyze charge density of each atom. It has been shown that 0.38 electrons per unit cell are transferred to I atom from the C atom layer which leaves a lot of holes.