This paper deals with the problems of both state estimation and unknown input reconstruction for a class of uncertain switched linear systems. A state equivalent transformation is considered to decouple the unknown inputs, and a reduced-order switched system is constructed. Then, a reduced-order switched observer is proposed such that the states of original switched system can be asymptotically estimated, and the sufficient conditions of switched observer design are provided by solving the feasibility of an optimization problem. A kind of method for unknown input estimation is given by using the some numerical approaches. Finally, the results of a numerical simulation show the effectiveness of the proposed method.