Iron ore is usually agglomerated after beneficiation to obtain the high-quality charge in China. Some complex iron ores need acid leaching or other chemical beneficiation to produce high-quality iron concentrate, this type of iron concentrate has the poor performance of green balls due to its weak surface hydrophilicity. To fully optimize this kind of minerals, in this paper, the magnetite concentrate after acid leaching dephosphorization is pretreated by water-washing deacidification, and the effect of water washing on the surface and pellet properties of iron concentrate is investigated in order to provide the theoretical basis and strengthening measures for pellet preparation of acid leaching dephosphorization concentrate. The results show that water-washing deacidification pretreatment can increase the ratio of the fine particles, and the surface area increased from 1 682 cm²/g to 1 853 cm²/g. The contact angle decreased from 33.77° to 31.82°, enhancing hydrophilicity and improving particles' physical stability. After water-washing deacidification, the strength of green balls and roasting performance of acid-leaching dephosphorized iron concentrate are improved. The drop strength increased from 1.0 times/(0.5 m) to 5.8 times/(0.5 m), and the compressive strength of fired pellets increased from 999 N/P to more than 2 500 N/P.