By means of Cliffords ordinal sum theory,according to the classification criteria of whether the outer operator G1 is a uninorm, the other two kinds of methods to constructing a new n-uninorm are given. Based on these methods, there are a number of new n-uninorms. Moreover, as an application, it is proved that the converse propositions of all decomposed theorems hold for all n-uninorms with continuous underlying functions in the relevant references.