This paper studies the non-fragile H∞ state observer design problem for a classof uncertain time delay systems by using the Lyapunov stability theory and thelinear matrix inequality technique. Several results which ensure these systems tobe asymptotic stability are obtained. The obtained results are given by the linearmatrix inequality and can be solved easily. Moreover, the gain matrix of theobserver can vary appropriately. Finally, a numerical simulation shows that theprovided results are effectiveness.