Lack of potassium in soil limits crop yield. Increasing yield and conserving potassium ore requires improving K use efficiency (KUE). Many genes influence KUE in plants, but it is not clear how these genes function in the field. We identified the V-type H+-pyrophosphatase gene EdVP1 from Elymus dahurica. Gene expression analysis showed that EdVP1 was induced by low potassium stress. Protein subcellular localization analysis demonstrated that EdVP1 localized on the plasma membrane. We overexpressed EdVP1 in two wheat varieties and conducted K tolerance experiments across years. Yield per plant, grain number per spike, plant height, and K uptake of four transgenic wheat lines increased significantly compared with WT; results from two consecutive years showed that EdVP1 significantly increased yield and KUE of transgenic wheat. Pot experiments showed that transgenic plants had significantly longer shoots and roots, and higher K accumulation in shoots and roots and H+-PPase activity in shoots than WT under low K. A fluidity assay of potassium ion in EdVP1 transgenic plant roots showed that potassium ion influx and H+ outflow in transgenic plants were higher than WT. Overexpressing EdVP1 significantly improved yield and KUE of transgenic wheat and was related to higher K uptake capacity in root.