Abstract: Based on CARIMA model,a multivariable pole assignment self-tuning control implicit algorithm fornonminimum phase system is proposed,in which bilinear parameter estimation method with one step relaxationand polynomial matrices exchange based on matrix expansion is introduced.In order to increase the robustness ofthe algorithm,two strategies are also introduced.Simulation results show that the proposed algorithm is robust toparameter and structure variations of the controlled plant.It also has good tracking and regulation properties withless computing time and insensitivity to initial set values.Hence it is a new algorithm of prospects for industrial application,especially for nonminimum phase controlled system.