Understanding the effects of structural properties on the lithium storage behavior of mesoporous TiO2 is crucial for further optimizing its performance through rational structure design. To achieve this, herein, the surface area and the grain size of the prepared mesoporous TiO2 are intentionally adjusted by controlling the calcination temperatures. It is found that the capacities of the mesoporous TiO2 contain both the lithium-ion insertion into the bulk phase (Q in) and the additional surface lithium storage (Q as). The Q in gradually increases with grain sizes to a steady level and then slightly drops. By contrast, the Q as is directly proportional to the specific surface area of the mesoporous TiO2 and is ascribed to the capacity originated from the lithium-ion insertion into the surface layer. The experimental comparison and analysis demonstrate that the fast kinetics of the Q as ensure both the better rate performance and capacity retention of mesoporous TiO2 than bulk ones. Specially, the mesoporous TiO2 calcinated at 350 °C shows the highest reversible specific capacity of 250.2 mA h g-1, the best rate capability (132.5 mA h g-1 at 2C) and good cycling stability. Our findings shed great light on the design of high-performance nanostructured TiO2 with surface lithium storage.