The invention relates to a regenerative thermal oxidation (RTO) treatment process for tail gas produced by an ammoxidation process. The RTO treatment process comprises a flue gas flow mixer, a waste gas heating and mixing box, a front induced draft fan, a flame arrester, an RTO incinerator, a flue gas mixing box, a static mixer, a selective catalytic reduction denitration (SCR) reactor, a plate heat exchanger, a washing tower, a rear induced draft fan and a chimney. According to the process, ammonia, hydrogen cyanide and nitrile-containing organic matters are synergistically degraded; and meanwhile, generated NOx is efficiently removed, and the treated waste gas stably meets national and local emission standards and requirements. The whole process has the advantages of high removal efficiency, high operation stability, low operation cost and the like; and the purification efficiency can reach 99% or above, the purification efficiency of generated secondary NOx can reach 90% or above, and emission is stable and meets national and local emission standards and requirements.