Na-doped Li3−x Na x V2(PO4)3/C (x =0.00, 0.01, 0.03, and 0.05) compounds have been prepared by using sol–gel method. The Rietveld refinement results indicate that single-phase Li3−x Na x V2(PO4)3/C with monoclinic structure can be obtained. Among three Na-doped samples and the undoped one, Li2.97Na0.03V2(PO4)3/C sample has the highest electronic conductivity of 6.74×10−3 Scm−1. Although the initial specific capacities for all Na-doped samples have no much enhancement at the current rate of 0.2C, both cycle performance and rate capability have been improved. At the 2.0C rate, Li2.97Na0.03V2(PO4)3/C presents the highest initial capacity of 118.9mAhg−1 and 12% capacity loss after 80 cycles. The partial substitution of Li with Na (x =0.03) is favorable for electrochemical rate and cyclic ability due to the enlargement of Li3V2(PO4)3 unit cells, optimizing the particle size and morphology, as well as resulting in a higher electronic conductivity.