Hexavalent chromium is one of most toxic heavy metal contaminants in biological and environmental systems, thus the electrochemical method with high-sensitivity, excellent-accuracy, low-cost and easy-operation is desired to be developed for detecting Cr(VI). In this work, carbon black (CB) modified glassy carbon electrode (GCE), was proposed as a sensor for monitoring Cr(VI) concentrations. CB is cheap, green, environmentally friendly, and incapable to secondary pollution. Moreover, the sp(2)-bonded CB possesses a great plenty of mesopores as the charge transport channels in interior surface to enhance the sensing efficiency. Thus CB modified GCE demonstrated an outstanding electrocatalytic performance for reduction of Cr(VI), with a wide linear concentration range from 0.025 to 483.225 mu M and a low detection limit (LOD) of 10 nM. The modified electrode also showed fast response, high stability, as well as good selectivity against interferences from other metal ions. These attributes suggest that CB as a metal-free electrocatalyst has an exciting prospects of sensing applications for determination of Cr(VI).