Three problems were summarized for the current situation of RTO device.Taking the design of RTO device for a fine chemical project as an example,the fire risk category was first defined,and the calculation method of mixed gas control concentration P and combustible gas concentration detector installation distance L was provided according to the design conditions.These provide a basis and support for the safety design of RTO device and can provide a reference for similar engineering design.The comprehensive safety design of RTO device was carried out from general drawing,process,pipeline,electrical,automatic control,civil construction and other aspects,which can prevent and reduce safety accidents from the source and improve the inherent safe level of the RTO device.