Zero‐dimensional nitrogen‐doped carbon dots (N‐CDs) have been proved effective when introduced into the polymerization system of aniline as the hard template to synthesis small‐sized, monodisperse and highly conductive N‐CDs/PANI (N‐CDs/PANI) nanocomposites, which were then added into acrylic (AC) resin to produce coatings with excellent corrosion resistance and antifouling performances in this paper. Compared with the PANI, the N‐CDs/PANI did show remarkably improved anticorrosion and antifouling properties. The protection efficiency of the AC resin coating was increased by 5 times and to 57.3% with the addition of the N‐CDs/PANI, which is higher than that of the AC resin coating, about 37.0%, with the addition of the PANI. In addition, the AC resin coating containing N‐CDs/PANI exhibited additional antifouling properties with an algae inhibition rate of about 24.6%, since the redox property of the carbon dots could destroy the photosynthesis of microorganisms such as Chlorella. Furthermore, because that the N‐CDs/PANI had better dispersibility than PANI and could be more uniformly dispersed in the AC resin, the adhesion of the N‐CDs/PANI‐AC coating was better than that of the PANI‐AC coating.