We present a theoretical treatment for the repeatedly dressed FWM processes in N5B five-level atomic system. Based on our previous work, the evolution of Autler-Townes splitting in a multi-dressed FWM spectrum is expounded using the characteristic method of Independence effect. Under condition that the coupling and probe fields which induced the FWM are strong, we further demonstrate the suppression and enhancement of FWM signal intensity. The results indicate that one cpupling field can dresse the atom twice and produce the donbly dressed state and triply dressed states. Many applications of multi-dressed FWM spectrum can benefit from the investigation on the atomic energy level and the nonlinear processes of mutiwave mixing(MWM).