For the control problem of a class of high-order unknown nonlinear systems with unmatched interference,a virtual recursive control method based on Auto-Coupling Proportional-Integral(ACPI) control theory is proposed.By introducing an unknown state and the concept of total disturbance,the unmatched nonlinear system is mapped into an equivalent linear unknown system,and a controlled error system excited by total disturbance in reverse phase is constructed.The ACPI virtual instructions with speed factor as the core linkage factor are constructed in combination with ACPI control theory.In order to effectively avoid the problem of “differential explosion” in back-stepping control,the differential of each virtual instruction is defined as unknown bounded disturbance.Simulation results show that ACPI control system not only has good dynamic quality and steady-state performance,but also has good robustness against disturbance,so it has a wide application prospect in the control field of high-order nonlinear unknown systems.