This study aims to explore the potential use of sentence tree-structure in English grammar teaching in college. After combining Schema Theory and Lexical Chunk Theory, the writer proposed the sentence tree-structure tool and tried to apply it in one of her grammar classes in college. During the teaching process, students were asked to analyze long and complex sentences from IELTS reading texts and to write paragraphs and essays for IELTS writing task two topics, with the purpose of applying the new tool in productive activities. Data collection instruments include a pre-test, a post-test, questionnaires and interviews. Both quantitative and qualitative analysis of the data was employed. The difference in students' performance in the pre-test and the post-test revealed that the majority of students showed improvement in their ability to analyze long complex sentences and there was an obvious decline in the number of sentence structure-related grammar errors in their writing. Students' responses in questionnaires and interviews showed a growth in their study motivation and positive perceptions towards the use of this new tool in their grammar learning.