Manganese　dioxide　crystallite　and　its　composite　hybridized　with　graphene　nanoribbons　(GNRs)　are　prepared　by　hydrothermal　method.　The　effects　of　reaction　temperature　and　time,　surfactant,　and　reducing　Mn　resource　are　discussed.　As　the　cathode　material　for　Li　battery,　gamma-MnO2　nanowire/nanorod　hybridizing　with　(GNRs)　(gamma-MnO2/GNRs)　shows　a　higher　discharge　specific　capacity　than　it　covering　with　carbon　nanotubes　or　graphene　sheets.　In　addition,　the　discharge　specific　capacity　of　gamma-MnO2/GNRs　is　much　higher　than　those　of　pure　beta-MnO2　and　compact　beta-MnO2/GNRs.　The　effects　of　crystal　size,　morphology,　and　GNR　hybrid　on　the　discharge　specific　capacity　are　discussed.