The in situ polymerization of aniline monomers within kaolinite interlayers easily led to an intercalated polyaniline (PANI)–kaolinite nanocomposite through a facile mechanochemical method. The X-ray diffraction results demonstrate that PANI was successfully intercalated in the interlayers of kaolinite, which was lightened by an increased basal spacing from 7.24 to 14.67 Å of kaolinite in the as-synthesized nanocomposite, and the characterization results from Fourier transform infrared spectrometry, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy further confirm this conclusion. The thermal stability of PANI was improved significantly when PANI was intercalated into kaolinite to form the nanocomposite; this was proven by thermogravimetric analysis. Moreover, a panel experiment was carried out under a simulated marine environment to evaluate the anticorrosive effect of the as-prepared product, and the results show that the epoxy resin/intercalated PANI–kaolinite nanocomposite coating had a better anticorrosive effect than that of the neat epoxy resin coating. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43551.