Uniformly dispersed carbon coated Sn-MnO nanocomposite (Sn-MnO@C) has been fabricated by thermal annealing of MnSn(OH)6 nanoparticles precursor in acetylene/argon gas (1/9; v/v). Benefiting from this unique method, the synchronously formed Sn and MnO nanocrystals both with size about 12nm were uniformly dispersed in the amorphous carbon matrix. Meanwhile, a porous structure appeared which could be attributed to the dehydration of MnSn(OH)6 in the calcination process. As the anode for lithium-ion batteries, the Sn-MnO@C nanocomposite demonstrates a reversible capacity of 684mA h g−1 after 280 cycles at a current of 100mAg−1. The fine electrochemical performance mainly attributes to uniformly dispersed nanoparticles, porous structure as well as amorphous carbon matrix coating.