The invention discloses a method for realizing continuous feedback control by duality of hot finishing outlet instruments, which particularly includes steps that instruments used for detecting production target parameters are integrated into a hot continuous rolling production line, wherein each production target parameter is detected by at least two instruments simultaneously and utilizes identical data output modes to output, a parameter detected by one instrument of each production target parameter is utilized as a measured signal while a signal detected by the other instrument of each production target parameter is utilized as a redundant signal, the measured signal and the redundant signal are transmitted to a control system to form functions of redundantly outputting finished product key quality target detection data, mutually diagnosing the redundant signal basically and automatically and fast switching, thereby realizing closed loop control of instrument detected information continuous participating feedback, effectively guaranteeing four basic quality indexes of finished steel strips, and increasing operating rate of a rolling mill. The method plays a strong guarantee for increasing yield, guaranteeing quality and reducing waste steel rate and safety accident rate.