A high-sensitive electrochemical immunosensor was prepared by immobilizing anti-HupA monoclonal antibody onto the glassy carbon electrode modified with a reduced graphene oxide/chitosan composite membrane.And an electrochemical immunosensor for the detection of huperzine A（HupA）was established as the antigen-anibody reaction could block the electron transfer of［Fe（CN）6］3-/4- redox system.The electrochemical behavior of HupA in［Fe（CN）6］3-/4- redox system was investigated by cyclic voltammetry（CV），electrochemical impedance spectroscopy（EIS）and differential pulse voltammetry（DPV）.Under the optimized conditions, there existed a good linearity between HupA concentration logarithm and the difference of peak current in the assay system of 15 mmol/L K3Fe（CN）6+0.1 mol/L KCl+0.1 mol/L PBS（pH 6.5） in range of 1.0×10-13-1.0×10-10 mol/L with a correlation coefficient（r）of 1.000 0.The detection limit was 3.0×10-14 mol/L, and the recoveries were in the range of 99.4%-102%.With the characteristics of strong specificity, high sensitivity, simple operation and environmental protection, this method could be used for the rapid detection of huperzine A in natural herbs.