Polydopamine (PDA) functionalized graphene/NiFe2O4 (GNSs–PDA–NiFe2O4) nanocomposite has been successfully synthesized through an in-situ ultrasonic method. The obtained GNSs–PDA–NiFe2O4 nanocomposite shows a reversible capacity up to 947mAhg−1 and much improved rate capability, e.g. delivering a capacity of 562mAhg−1 at 5Ag−1, about 7 times higher than that of graphene/NiFe2O4 nanocomposite. The improvement in the rate capability of the obtained GNSs–PDA–NiFe2O4 nanocomposite can be attributed to the improved interactions between graphene and NiFe2O4 derived from PDA, and a high conductive network fabricated by PDA functionalized graphene, which can be supported by TEM images and EIS measurements. Further studies reveal the strong graphene–NiFe2O4 interactions are also beneficial for retaining the high conductive network after the charge–discharge processes, and further beneficial for its cyclic stability.