In this work, fine powders of K0.5Na0.5NbO3 (KNN) are produced by a single step of solution combustion synthesis (SCS) using glycine as the reductant fuel and potassium & sodium nitrates as the oxidizers, which are mixed with niobium oxide. Single phase of KNN products can be successfully prepared in a one-step SCS by adjusting the glycine-nitrate ratio. It is concluded that the stoichiometric or slightly fuel-excess condition is good for the single step production of KNN. The one-step SCS of KNN also shows good scaling-up productivity, which can be ignited by both electric heating and microwave heating. This work may provide a feasible large-scale production of various functional oxides by a one-step SCS process.