The florisil was used as adsorbent for the removal of ammonia nitrogen from low concentration petrochemical wastewater. The florisil was characterized by BET, SEM and XRF, respectively. The effects of the ratio of agent to liquid, adsorption time, pH, adsorption temperature and initial mass concentration of ammonia nitrogen on the effect of adsorption and removal of ammonia nitrogen were investigated. The results show that when the initial concentration of ammonia nitrogen is 50.00 mg/L, the ratio of agent to liquid is 2 g/L, pH value is 7, the adsorption temperature is 293.15 K, and the adsorption time is 5 min, the adsorption effect of the florisil presented superior performance. When the petrochemical wastewater with low concentration of ammonia nitrogen is treated under these conditions, the ammonia nitrogen concentration decreased from 17.53 mg/L to 5.16 mg/L, and the removal rate reached 70.6%, meeting the emission standard of GB 31570-2015.