In recent years, modification of electrode surfaces with various electroactive materials is an interesting area of research in designing electrochemical sensors. Electrochemical sensors have eliminated slow preparation and the use of expensive reagents, and have provided low cost analytical tools. Nevertheless, the electrochemical sensors offer numerous applications in clinical diagnosis, environmental monitoring and food analysis. Among the various mediators used for electrode modification, solid metal hexacyanoferrates have attracted attention of electrochemists as excellent electron transfer mediators. These materials show interesting redox chemistry that is accompanied by changes in their electorchromic, electroanalytical, ion-exchange, and electrocatalytic properties. This paper reports demonstrates the development of an electrochemical sensor based on MWCNT/cystiamine/CuHCF nanocomposite (MWCNT/Cys/CuHCF) modified graphite electrode for detecting Epinephrine, Ferulic acid and Riboflavin (EP), Ferulic acid(FA) and Riboflavin (RB) in 0.1 KNO3 (pH 7) using voltammetric studies. The modified graphite composite electrode (GCE) was prepared by depositing appropriate amounts of Ni on the surface of MWCNT/Cys/GCE, followed by electrodepositing nickel hexacyanoferrate (CuHCF) . The morphology and the interface properties of composite were examined by UV-visible, scanning electron microscopy, HRTEM, Raman spectroscopy, electrochemical impedance spectroscopy. The modified electrode exhibits excellent sensing performance for detecting EP with linear range from 0.2 μM to 3.0 μM and a detection limit of 0.0101 nM (S/N = 3). Under optimal conditions, the sensor displays excellent stability and satisfactory results in real samples analysis.