A novel two-dimensional nanocomposite, polyaniline-coated laponite (polyaniline/laponite) nanosheets, has been prepared by in situ oxidative polymerization of aniline on the surface of laponite nanosheets. These sheets present a loosely stacked structure with the formation of a great number of pores, which it can provide a larger electrode/electrolyte contact surface area, shorten the path for ions transport in the active material, and alleviate the expansion and contraction of the electrode material during the charge/discharge processes, leading to an improved electrochemical performance. As an active material for supercapacitors, the specific charge/discharge capacitance of polyaniline/laponite nanosheets is 375 and 330 F g(-1) (based on the total working electrode mass) at a current density of 0.5 A g(-1), respectively, with a coulombic efficiency of 88 % which is higher than that of pure polyaniline (28 %). Moreover, polyaniline/laponite nanosheets also show a good rate capability with a growth of current density from 0.5 to 30 A g(-1), a specific discharge capacitance of 266 F g(-1) remained at 30 A g(-1). This work suggests a strategy to improve the electrochemical performances of polyaniline.