This study was conducted to investigate the removal characteristics of PO_4^-3-P contained in livestock wastewater using waste concrete. With small particle size, increased dosage and temperature of water, PO_4^3--P was well removed by waste concrete. PO_4^3--P was removed by adsorption reaction in low pH of the primary phase, but the crystallization reaction predominated for increasing pH with passed time. As a result of adapting the adsorption isotherm equation, PO_4^3--P removal was more affected by the crystallization reaction than the adsorption reaction. In the SEM micrograph, there was no evident change on the waste concrete surface. Particle size was plate-phase before reaction but appeared a dense form to progress in the crystallization reaction after reaction.