Abstract: This is an article in the field of ceramics and composites. Hydroxyapatite (HAP) has excellent ion exchange performance, shows good adsorption capacity for heavy metal ions, harmful anions, and organics in wastewater, and will not cause secondary pollution in the process of wastewater treatment. Thus, it is a promising green adsorbent. Due to its small size and large specific surface area, nano-hydroxyapatite (nHAP) exposes more adsorption sites, showing supreme adsorption capacity. It is a tendency to produce nHAP composites of strong adsorption capacity, easy for solid-liquid separation and regeneration, and low-cost. This article reviews the recent research progress of nano-HAP and its composites as adsorbents for wastewater treatment, and prospects the application of them as adsorbents.