In this paper, a decentralized adaptive approximation-based output feedback control scheme is developed for a class of uncertain switched stochastic nonlinear interconnected systems. Fuzzy logic systems (FLSs) combined with adaptive backstepping method are applied to model the unknown nonlinear functions of the switched system. The full-order observer is designed to estimate the immeasurable states and the dynamic surface control (DSC) technique is adopted to ensure the computation burden is greatly reduced. Moreover, the proposed controllers guarantee the semi-global bounded of the resulting closed-loop system under any switching laws. Simulation results show the effectiveness of the proposed control scheme.