To improve the oral English communicative competence of post-graduate students in science and technology, it was decided to use seminar techniques as the principal method in Lanzhou Seismological Institute. After a first stage which provided essential knowledge of English structure, special topics were chosen and related reading materials assigned. After careful preparation, discussion was done in class with questioning and debating together. The seminar technique helped students to learn foreign culture, science and technology, as well as the foreign language. The seminar approach seemed especially helpful for these post-graduate students in giving scope to their special skills and interests, developing their intelligence, cultivating their creative ability and providing a variety of practical communicative situations and a relaxed environment. The seminars helped them to lose their communication apprehension, reinforce their learning of oral English skills and evaluate their own success. Altogether 90 hours were spent on seminar-style work, and the outcome was a breakthrough in the students' communicative competence. This paper describes the work done and discusses some of the advantages of the approach.