In this work the effect of the precursor graphite on the structure and morphology of the graphene oxide and reduced graphene oxide are investigated by considering three different sizes source graphite such as 2-15, <45 and 170-840μm respectively. All the three graphite were oxidized by Modified Hummer’s method and further reduced by hydrazine hydrate by maintaining same synthesis conditions. The results demonstrated that the oxidation process is size dependent of the source graphite.The results revealed that smaller size graphite is fully oxidised as compared to larger sizes and also functionalized more. Few layers (less than 4-5) crystalline, less disorder and unfolded reduced graphene oxides are obtained when smallest size graphite is used as the source material. The water molecules present in the graphene oxide synthesised from larger size graphite as source material are higher and that can lead to the the occurrence of polycrystalline in structure, more disorder and wrinkled or folding reduced graphene oxide. Therefore, this study can open a new pathway to synthesis more crystallinity, less disorder and wrinkled free or unfold reduced graphene oxide for several potential applications.