Graphene oxide can be prepared from graphene by introducing hydrophilic functional groups to facilitate dispersion in water. This process has attracted significant attention for production of fillers for polymer composite materials. Alginate is a natural polymer that can be used as a composite fiber matrix that is industrially applicable and is currently being studied for the development of novel materials. Graphene oxide/alginate composite fibers were prepared with various graphene oxide contents by wet spinning in a calcium chloride coagulation solution. To improve thermal and electrical properties, the graphene oxide/alginate fibers were reduced using hydrogen iodide and acetic acid. After low temperature carbonization over a graphite nickel catalyst, the yield of the carbonized alginate precursor increased from 20.3% to 36.1% upon addition of graphene oxide. After reduction and carbonization, XRD analysis showed the presence of a 2θ=26.4 ° peak arising from the (002) plane of the graphite structure. In addition, electrical conductivity increased from 225 to 13575 S/m, indicating that the composite fibers successfully incorporated graphite.