In summary, hollow carbon spheres (HCS) consisting of porous shells were prepared by pyrolysis of core–shell crosslinked and non-crosslinked block copolymers. Due to the unique structure advantages, the HCS served as an excellent matrix for the growth of PANI. The nano-PANI/HCS composite was synthesized via in-situ chemical oxidative polymerization of aniline. Four composites with different PANI mass loadings were synthesized by adjusting the reaction time. The effect of polymerization time of aniline on morphologies and supercapacitor performances were studied in detail. The supercapacitive performance of nano-PANI/HCS composite is strongly relied on the mass of PANI on the HCS. When the polymerization time of aniline was 6 h, the maximum specific capacitance of 435 F g−1 was achieved. In addition, the composite electrode material also has a good cyclic stability (≈60% remain of initial capacitance after 2000 cycles). All these attractive features make this nano-PANI/HCS composites promising for supercapacitor applications.