Tin dioxide (SnO2) is one of the most promising anode materials for the next generation Li-ion batteries due to its high capacity. To solve the problems caused by the large volume change (over 300%) and the aggregation of the tin particles formed during cycling, nano SnO2/C composites are proved to be ideal anode materials for high performance Li-ion batteries. However, it is still a challenge to disperse ultrasmall (<6nm) SnO2 nanoparticles with uniform size in carbon matrix. Here, we report a facile hydrothermal way to get such optimized nano SnO2/C composite, in which well dispersed ultrasmall SnO2 nanocrystals (3∼5nm) are embedded in a conductive carbon matrix. With this anode, we demonstrate a high stable capacity of 928mAhg−1 based on the total mass of the composite at a current density of 500mAg−1. At high current density of 2Ag−1, this composite anode shows a capacity of 853mAhg−1 in the first charge, in such high current density, we can even get a capacity retention of more than 91% (779mAhg−1) after 1000 cycles.