In this study, a sensitive electrochemical method for tetrabromobisphenol A (TBBPA) detection was presented based on an poly(diallyldimethylammonium chloride) modified graphitic carbon nitride-N-butylpyridinium hexafluorophosphate doped carbon paste electrode (CPE). Interestingly, in contrary to the poor electrical conductivity, graphitic carbon nitride (g-C3N4) was found to improve the electrochemical performance of the pure CPE. N-butylpyridinium hexafluorophosphate (NBH), a kind of ionic liquid, was tended to promote the charge transfer of the g-C3N4 doped CPE. While g-C3N4 and NBH were doped into CPE, the g-C3N4-NBH composite presented better promotion to the oxidation of TBBPA. After the parameters were optimized, TBBPA was detected with differential pulse voltammetry in the range of 1 nM to 30 nM and 30 to 500 nM with the detection limit of 0.4 nM. The prepared electrode owned the advantages of fairly simple, green and pleasurable sensitivity. Finally, it also could be used to detect TBBPA in the practical samples. (C) 2017 Elsevier Ltd. All rights reserved.