The direct and efficient removal of multiple heavy metal ions from acidic wastewater is a challenge. In this study, an efficient adsorbent of polyvinyl alcohol with abundant phosphate functional group (P-PVA) was designed and prepared for the simultaneous removal of multiple heavy metal ions (i.e., Cd2+, Cu2+, and Pb2+) from acidic wastewater. The characterization results indicated that abundant phosphate functional groups can be grafted with polyvinyl alcohol. Under acidic conditions (pH = 3), the adsorption results of P-PVA adsorbent show rapid removal of Cd2+, Cu2+, and Pb2+. The maximum adsorption capacities of 210.21 mg/g, 140.76 mg/g, and 235 mg/g were obtained for Cd2+, Cu2+, and Pb2+ ions, respectively. The adsorbent also shows high adsorption capacity in the presence of humic acid or coexisting cations (i.e., K+, Ca2+, and Mg2+). Competitive adsorption behavior under various systems showed binding strength of P-PVA in the order Pb2+ > Cd2+ > Cu2+. The adsorption mechanism of heavy metal ions was mainly governed by the complexation reaction between the phosphate functional group of P-PVA and heavy metal ions. This new adsorbent has a very high potential for practical application in the treatment of acidic and complexly polluted wastewater.Graphical Abstract: