Micro-nano structured LiFe1 − x Mn x PO4/C (0 ≤ x ≤ 0.05) cathodes were prepared by spray drying, followed by calcination at 700 °C. The spherical LiFe1 − x Mn x PO4/C (0 ≤ x ≤ 0.05) particles with the size of 0.5 to 5.0 µm are composed of lots of nanoparticles of 20 to 30 nm, and have the well-developed interconnected pore structure. In contrast, when Mn doping content is 3 mol% (x = 0.03), the LiFe0.97Mn0.03PO4/C demonstrates maximum specific surface area of 31.30 m2/g, more uniform pore size and relatively better electrochemical performance. The initial discharge capacities are 161.59, 157.04 and 153.13 mAh/g at a discharge rate of 0.2, 0.5 and 1 C, respectively. Meanwhile, the discharge capacity retentions are ∼100% after 120 cycles. The improved electrochemical performance should be attributed to higher specific surface, smaller polarization voltage, and a high Li+ diffusion rate due to the micro-nano porous structure and lattice expansion produced by Mn doping.