English is one of the most important languages in the world. English grammar is a compulsory course for Chinese students. However, there are many factors causing difficulties for Chinese students to learn English grammar at college. This paper focused on analyzing the factors that cause difficulties for Chinese college students to learn English grammar at college. The factors of weak foundation in English grammar, the differences between Chinese and English, the development of English grammar, the differences between American English and British English, and the more advanced grammar knowledge at college have been analyzed. To help college students learn English grammar more effectively and efficiently, some suggestions have been proposed. For example, the students should spend more time learning English grammar at elementary school and middle school so as to build up a solid foundation for English grammar. English teachers should keep on learning and equip themselves with the latest English grammar knowledge.