This paper investigates the input-output decoupling problem of singular Boolean control networks (SBCNs) by using the semi-tensor product method. First, the dynamics of SBCNs are converted into algebraic forms via the matrix expression of logical functions. Then, if the problem is solvable desired state feedback controllers to solve it are designed by solving a set of logical matrix equations. In addition, necessary and sufficient conditions for the solvability of input-output decoupling problem of SBCNs are obtained. Finally, an illustrative example is given to show the effectiveness of the obtained results.