Electrically conductive polymer composites (CPCs) consisting of dispersed conductive filler in a polymer matrix continue to attract increasing academic and industrial research. A facile strategy to synthesize an Ag/rGO/epoxy conductive composite by a one-pot fabrication process is proposed. The effects of the preparation parameters of the one-pot approach on the conductivity, structure, and chemical composition of Ag/rGO composite are investigated, and the correlation between the preparation parameters and the conductivity of Ag/rGO is established. In this study, Ag/rGO is prepared by using a solution oxidation-reduction method with green reductant Vitamin C. The Taguchi method and response surface methodology are used to evaluate the optimum preparation parameters. The rank of control factors for conductivity follows the order [Vitamin C] > reaction time > [AgNO3]. The optimum electrical conductivity of Ag/rGO is 123.00 S/cm with the optima preparation parameters [Vitamin C] = 2.0 g/L, [AgNO3] = 0.1 g/L, and reaction time = 6 h. In a one-pot process, the amount of available Vitamin C for the reduction of GO is an important factor. Experimental results indicate that m(Vitamin)(GO)/m(GO) >= 1.0 is required to ensure sufficient reduction of GO. The uniform Ag particle size distribution is crucial to obtain higher conductivity. The Ag/rGO/epoxy composite can be prepared by one-step in-situ reduction. Experimental results show that Vitamin C can reduce GO and Ag+ to rGO and Ag particles during polymerization of epoxy. Conductive polymer composite with conductivity as high as 17.09 S/cm can be prepared.