Lawrence’s writing is heavily influenced by his social background. He is in an incompatible family, for his parents come from different social classes. His sensitiveness to class distinctions brought about by his family background is deeply rooted in his writings. Novel Sons and Lovers is this typical work. One of the distinctive features of the novel is the use of two language varieties which expresses the bilingual situation of the Morels’ family in Sons and Lovers. The writer Lawrence alternatively uses two language varieties in dialogues to reveal the psychology of the characters and the most characteristic of his theme: class conflict. This study researches into the use of language varieties of three major characters (Mr. Mo-rel, Mrs. Morel and their son Paul) in Sons and Loversfrom the viewpoint of code switching to discover how class conflict is presented by alternative use of language varieties. To appreciate and deeply understand the novel, it is necessary to know the application of code switching in this work.