Three-dimensional carbon nanofibers embedded with Na2MnPO4F nanoparticles are fabricated via electrospinning method and investigated as cathode material for sodium ion batteries. The Na2MnPO4F nanoparticles with a size of about 10-30 nm are well-crystallized and the diameter of the carbon nanofibers are about 100 nm. Due to the ultrafine particle size of Na2MnPO4F together with high conductivity of the three-dimensional electron/ion hybrid network of carbon nanofibers, the material synthesized at 650 degrees C exhibit good electrochemical performance at room temperature. It is found that an obvious potential platform as high as 3.6 V during charge/discharge processes occurs and there is an initial specific capacity of 122.4 mAh g(-1) at 0.05C rate, which is close to the theoretic capacity (one Na extracted) of Na2MnPO4F. This work suggests a new design strategy for high-performance Na2MnPO4F cathodes of sodium-ion batteries.