TiO2 mesoporous single crystals (MSCs) with diverse constructions in a controllable fashion are successfully fabricated by a new template-free method for the first time, using oxalic acid (OA) as the pore-forming agent and morphological controller. Unlike the seeding-template based growth mechanism, the TiO2 MSCs in the present work may involve a process of oriented aggregation and crystallographic fusion of primary nanocrystals. The structural control of TiO2 MSCs can be easily realized by tailoring growth conditions, such as Ti-source concentration and OA dosages. Moreover, the TiO2 MSCs shows substantial improvement in lithium specific capacity from 0.2C to 10C in comparison to the reference TiO2 nanoparticle. The high-rate performance was further improved by fabricating MSCs/graphene oxide nanocomposites, and specific capacity of the composite at the rate of 20C is as high as 90mAhg−1. This new template-free strategy may open up new and exciting opportunities for the preparation of other MSCs, and makes important applicatory significance for the structure design of high-rate lithium ion battery anodes.