Based on generalized Apell-Четаев constrained conditions and taking into a ccount the inherent higher-order nonholonomic constraints,the generalized Poincaré-Cartan integral invariant for a generalized mechanical system with higher- order subsidiary nonholonomic constraints is formulated. We can show that the ex istence of Poincaré-Cartan integral invariant for such a system is equivalent to the generalized canonical equation of a nonholonomic constrained generalized mechanical system.