For a class of generalized discrete Duffing systems with periodic excitations,a fast-slow analysis method is applied to simulate the system by time course diagrams and bifurcation diagrams to obtain new types of cluster oscillations under different parameters and to explore the connection between them and continuous Duffing systems.The cluster oscillation modes are divided into two categories,one is the symmetric cluster oscillation induced by the attractor transitions when the slow variable crosses the Fold bifurcation point or the chaotic excitation point,and the other is the asymmetric cluster oscillation induced by the delayed Flip bifurcation when the slow variable cannot cross the Fold bifurcation point or the chaotic excitation point.