In the present research work, 2D-Porous NiO decorated graphene nanocomposite was synthesized by hydrothermal method to monitored the concentration of epinephrine (EPI). The morphology (SEM and TEM) results confirmed 2D-Porous NiO nanoparticles firmly attached over graphene nanosheets. FTIR and XPS analysis confirmed the formation of nickel oxide formation and complete reduction of GO to rGO. The electrochemical activity of the proposed NiO-rGO/GCE modified electrode on epinephrine was analyzed by simple cyclic voltammetry technique. The proposed low cost NiO-rGO/GCE modified electrode showed excellent catalytic activity over GCE and rGO/GCE electrodes. Due to its high conductivity and charge transfer ability of the NiO-rGO/GCE modified electrode exhibited high sensitivity of EPI at optimized conditions. The anodic peak current of the EPI linearly increases with increasing the concertation of EPI. A wide linear range (50 μM-1000 μM) was achieved with high correlation coefficient (R2 = 0.9986) and the limit of detection (LOD) of NiO-rGO/GCE modified electrode was calculated to be 10 μM. NiO-rGO/GCE electrode showed good stability and repeatability towards the EPI oxidation. Mainly, the proposed NiO-rGO/GCE modified electrode showed good sensitivity of EPI in the human biological fluid with high recovery percentage. The low cost, NiO-rGO/GCE electrode could be the promising sensor electrode for the detection of Epinephrine in the real samples.