Abstract: Liquid metals have good wetting properties, and thus the incipient boiling superheat is usually very high. However, the existing of oxide layer which has bad wetting properties can significantly reduce the incipient boiling superheat. In order to study the oxide layer effects, an oxide layer effect model was established and verified by test data. The results show that the nucleation process under the effects of oxide layer can be divided into two types, i.e. the direct nucleation and the nucleation after interface movement. The nucleation radius under the oxide layer effect should be between the values of the oxide layer location and the deepest interface location, and the best estimated value is their geometric mean.