Acrylonitrile wastewater is a kind of highly toxic industrial wastewater, but it contains a lot of valuable chemical materials. In this study, by using the most promising hydrothermal technology, we investigated the best reaction conditions and possible reaction pathways for the conversion of the three nitrites (acrylonitrile, acetonitrile, and succinonitrile) to organic acids under alkaline hydrothermal conditions. Then, the reaction conditions for the conversion of actual acrylonitrile wastewater to organic acids were further optimized. The actual wastewater of acrylonitrile was converted into 1.33 x 10(4) mg/L acrylic acid, 1.98 x 10(4) mg/L formic acid and 9.40 x 10(3) mg/L acetic acid at optimal reaction conditions (reaction temperature 300 degrees C, reaction time 90 s, and initial NaOH concentration 1.0 mol/L). It is the theoretical basis of the application of the hydrothermal alkali-catalyzed method in the acrylonitrile wastewater resource engineering. (C) 2020 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.