In this study, we report the growth of core-shell GaAsP nanowires using metal-organic chemical vapor deposition. Detailed electron microscopy investigations indicate that the grown core-shell nanowires have the P concentration in the nanowire cores higher than that in the shells. It finds that Au catalysts enhance the local decomposition of PH3, leading to relevant high P incorporation in nanowire cores during nanowire growth. These core-shell GaAsP nanowires exhibits enhanced electrical conductivity when compared with uniform GaAsP nanowires, which is attributed to the accumulation of carriers at the core/shell interfaces due to band offset between the core/shell regions. This study provides an approach to enhance electrical conductivity of III-V semiconductor nanowires.