Steel slag is a commercial waste material mainly containing SiO2, Al2O3, and CaO which are the chemical components of zeolite and hydroxyapatite (HAP), respectively. From the steel slag, a hydroxyapatite-zeolite composite material (HAP-ZE) was successfully synthesized in a one batch system by adding H3PO4 and NaOH. The structural characteristics of HAP-ZE were investigated by XRD, SEM, and N-2 adsorption. From the adsorption of VOCs, HAP-ZE was found to have adsorption properties comparable to those of pure zeolite and HAP.