The invention proposes a two-input two-output network decoupling 
control system (TITO-NDCS) unknown time-
delay two-degree-of-freedom IMC method, which belongs to the technical field of a TITO-NDCS with limited bandwidth resources. In the face of the mutual influencing and 
coupling of two-input two-output signals, a decoupled TITO-NDCS shall be put in place, and since when the 
network data are transmitted among the nodes, network time 
delay occurs. This not only influences the stability of the closed-
loop control circuits, but also impacts the stability of an entire 
system, and can even lead to the 
instability of the TITO-NDCS. Considering this, the 
network data transmission process among all real nodes in the TITO-NDCS is proposed to replace the network time 
delay compensation models among them, and at the same time, through the two-degree-of-freedom IMC to two loop circuits, it is possible to eliminate the measurement, 
estimation and identification of the network time delay among the nodes, to reduce the requirement for 
clock signal synchronization, to reduce the influence of the unknown network time delay on the stability of the TITO-NDCS, and to improve the 
system control quality.