Metal sulfides have recently emerged as a new class of anode materials for lithium ion batteries. In this work, a facile method based on anion exchange reaction is reported to prepare nanowire interwoven NiCo2S4 nanowall arrays through topotactical transformation from the Ni-Co carbonate hydroxide precursor. The nanowire interwoven NiCo2S4 nanowall arrays are investigated as binder free anodes for lithium ion batteries. The electrochemical measurements reveal that the NiCo2S4 nanowall arrays possess large reversible capacity, good cycling stability and good rate capacity, making them promising anodes for advanced lithium ion batteries.