Abstract: The present paper presents the design, construction and uses of Chinese Science and Engineering Majors Written English Corpus (CSEMWEC). The learner variables of CSEMWEC include text source, level proficiency, education background and major; the task variables of CSEMWEC include text type, time limit and use of reference tools. CSEMWEC consists of three sub-corpora, EGP, EOP and EAP, with a total of 325.6 million running words. It is expected to inform the development of English writing standard for Chinese Science and Engineering Majors, the construction of the autonomous teaching-learning platform, interlanguage phraseological studies, longitudinal interlanguage studies, translation studies and so on.