An efficient detection of lethal environment pollutants via the simple and sensitive analytical method has drawn the central importance. In this work, the cotton flower like structured gold nanoparticle decorated functionalized carbon black/polytyramine (f-CB-PTy-Au) ternary nanocomposite was synthesized via the sonochemical synthesis method. The strong covalent interaction between the hydroxyl and amine group from the f-CB and PTy enhances the polymerization. Besides, the flower shaped gold nanoparticles (AuNPs) decorated on the surface of the f-CB-PTy via the non-covalent interaction. The structural properties of the f-CB-PTy-Au nanocomposite were probed by various spectrophotometric techniques. Then, the as-prepared nanocompositewas used to fabricate the electrochemical sensor for the amperometric determination of hazardous pollutant hydroquinone (HQ). Outstandingly, the proposed sensor demonstrated the wide linear response ranges from 0.006 mu M to 2400 mu M and the lowest LOD value around 0.1 nM was achieved. The favorable sensitivity of the proposed sensor was calculated about 3.423 mu A mu M-1 cm(-2). Furthermore, the practical applicability was investigated in different water samples such as tap water, waste water and river water. (C) 2019 The Electrochemical Society.