High-entropy perovskite oxides are promising materials in the field of electrocatalysis due to their advantages such as large spatial composition regulation, entropy effects, and tunable material properties. However, the preparation of high-entropy perovskite oxides with stable and controllable structures still remains challenging. Herein, we fabricated a series of high-entropy perovskite oxide porous nanotubes (PNTs) by electrospinning as efficient electrocatalysts for the nitrate reduction reaction (NO 3 RR). We further revealed that the different diffusion and decomposition behaviors of metal ions and polymers during the calcination process are the key to the formation of high-entropy perovskite oxide PNTs. Especially, LaSrNiCoMnFeCuO 3 PNTs show excellent performance of the NO 3 RR, achieving the maximum NH 3 Faradaic efficiency of almost 100%, yield rate of 1657.5 μg h -1 mg cat. -1 , and durable stability after successive cycling, being one of the best electrocatalysts for the NO 3 RR. The mechanism studies show that the charge redistribution induced by the multisite synergistic effect and abundant unsaturated sites in the high-entropy perovskite oxide PNTs favors the adsorption of NO 3 - and key intermediates and reduces the catalytic energy barrier, thus further achieving high NO 3 - conversion efficiency.