The TNT red water in the process of TNT production was pretreated by the complex extraction using trinoctylamine as a complex extraction agent. Seeing the removal rate of chemical oxygen demand (COD) and recycle use of extraction agent as goal, the effect of pH value, stirring speed, stirring time and the ratio of extraction agent and wastewater on the extraction efficiency was investigated. A study of intermittent experiment and continuous experiment was carried out. Results show that the extraction efficiency is the best when pH value is 0.9, stirring speed is 220 r·min^-1, stirring time is 30 min. When the volume radio of the extraction agent and wastewater is 2.4, the COD removal rate of common TNT red water reaches 99.4% by realizing the control of content of COD in effluent water via changing the extraction phase ratio. The COD removal rate of military TNT red water reaches 99.0%. When the volume ratio of extraction agent and wastewater is 2.3-2.4, the extraction agent can be recycled.