Based on the engineering example, slaughter-house wastewater can be treated by the two-stage biological contact oxidation process. The engineering example shows that the two-stage biological contact oxidation process is feasible for slaughter-house wastewater treatment. With the influent of COD 2780 mg/L, the COD of effluent is less than 49 mg/L. The operation expenses of the unit are presented. The quality of the effluent water is up to the second level in the Beijing Standard.