Based on the theory of interlanguage, the phenomenon of fossilization, and contrastive analysis, this paper illustrates the causes of Chinglish in students' learning by giving examples. It reveals that Chinglish is closely related to cultural differences and linguistic differences which are gaps between Chinese and English. In addition, students' inadequate exposure to authentic English and insufficient practice can turn their language errors gradually into a habit. Hence, it can be essential to further analyze the causes of Chinglish from these three aspects.