The traditional English teaching focuses on the grammar and sentence structure but ignores the relationship between the sentences and paragraphs thus causing students’ lack of awareness of using cohesive devices. This study aims to illustrate the cohesion and coherence problems in college students’ writing. As one of the four basic language skills, English writing skill is the most indispensable but complicated one for English learners to master. According to College English Curriculum Requirement and under the theoretical framework of Halliday and Hasan’s Cohesion Theory, this study finds out the misuse of reference, substitution, ellipsis, conjunction and lexical cohesion in students’ English writing. By illustrating the examples of the discourse errors in students’ English compositions, this study tries to put forward some suggestions to ameliorate traditional English teaching and improve students’ writing skill.