<span lang="EN-US">Intralingual comparison in language learning is an effective teaching </span><span lang="EN-US">method</span><span lang="EN-US">, which introduces </span><span lang="EN-US">a new </span><span lang="EN-US">learning from what students have mastered to what they are going to learn. The study is to investigate the effects of applying intralingual comparison on the teaching of English adverbial relative clauses to Chinese Senior high school students. Data was collected utilizing both quantitative and qualitative methods in a mixed method design. Data was gathered via experimental research (n=103) and semi-structured interview (n=12). The experimental group’s posttest scores improved statistically significantly after intervention. Research findings suggest that applying intralingual comparison i</span><span lang="EN-US">n</span><span lang="EN-US"> teaching could be considered as an effective teaching method in improving students</span><span lang="EN-US">’</span><span lang="EN-US"> performance </span><span lang="EN-US">on </span><span lang="EN-US">learning English adverbial relative clauses.</span><span lang="EN-US"> Besides, students would </span><span lang="EN-US">have more active and positive attitudes</span><span lang="EN-US"> toward</span><span lang="EN-US"> learning adverbial relative clauses</span><span lang="EN-US"> than the traditional teaching method.</span>