FeCO3 nanomaterials have been intensely investigated as anode materials for LIBs due to their high capacity, low cost and natural abundance. Nevertheless, the slow diffusion of lithium ions and its low electronic conductivity in the bulk materials limit the power performance of FeCO3. Developing an efficient strategy to promote the durability of FeCO3 is important. Here, an effective method is reported to significantly enhance the capacity and durability of the FeCO3 as anode materials. The FeCO3/carbon nanotubes composites (FeCO3/CNTs) are prepared via a facile, economical and effective single step in situ crystallization route, using carbon nanotubes, ferrous sulfate and urea as raw materials. The effects of CNTs content on the morphology, electrochemical performances and cyclic stability are fully investigated for these FeCO3/CNT electrodes. The addition of moderate CNTs can remarkably improve the electrochemical performances of FeCO3. FeCO3/CNT-15 delivers an initial discharge capacity of 1436 mAh·g−1 at the current density of 200 mA·g−1 and maintains a capacity of 694 mAh·g−1 after 140 cycles. With the merits of high-performance, low cost and facile synthesis route, FeCO3 nanorods interwind with CNTs should be an attractive candidate as anode material for high-performance lithium-ion batteries.