Abstract: Setting up the configuration bifurcation equation of the axisymmetric vectoring exhaust nozzle(AVEN) and utilizing the homotopy tracing approach,the configuration bifurcation behaviors of the AVEN driving parallel mechanism and the driving kinematic chains of the divergent flaps were analyzed.It is found that whether deflecting or not,the turning points will exist corresponding to the bifurcation parameter of the area exhaust nozzle,and the turning points will disappear corresponding to the bifurcation parameters of the deflecting angle.While the AVEN is in non-vector status,the driving kinematic chain of divergent flaps is at its multi-singular position.Both the turning points and multi-singular positions will lead the motion of the AVEN uncertain.This kind of motion uncertainty is harmful to the safety of aircrafts equipped with the AVEN.