In this paper, we analyze and characterize all solutions about α-migrativity properties of the five subclasses of 2-uninorms, i. e. Ck, C0k, C1k, C01, C10, over semi-t-operators. We give the sufficient and necessary conditions that make these α-migrativity equations hold for all possible combinations of 2-uninorms over semi-t-operators. The results obtained show that for G∈Ck, the α-migrativity of G over a semi-t-operator Fμ,ν is closely related to the α-section of Fμ,ν or the ordinal sum representation of t-norm and t-conorm corresponding to Fμ,ν. But for the other four categories, the α-migrativity over a semi-t-operator Fμ,ν is fully determined by the α-section of Fμ,ν.