The invention discloses a solid hazardous waste decontaminating treatment device, comprising a Fenton oxidation detoxication reaction device, a stabilization/solidification device and tail gas absorption devices, the Fenton oxidation detoxication reaction device is connected with an agitation conveying device, a pipeline of which is respectively connected with a feed hopper, an H2O2 dosing deviceand a ferrite dosing device; the Fenton oxidation detoxication reaction device is connected with the stabilization/solidification device via a conveying belt above which a stabilization/solidification medicine dosing device is arranged; both the Fenton oxidation detoxication reaction device and the stabilization/solidification device are provided with the tail gas absorption devices. The inventive device can oxide and fix the pollutants of the solid hazardous wastes to reduce hazard of contaminating the environment, and meanwhile, avoids secondary contamination resulted from waste gas. The Fenton oxidation detoxication reaction device and the stabilization/solidification device in the inventive device can be used in a disassembled state in order to treat the solid hazardous wastes having simple ingredients.