Since the outbreak of covid-19 pandemic from early 2020, blended learning has been appreciated and widely applied in Vietnamese universities in general and in the National Economic University in particular. There are some challenges for both teachers and students because this is the first time blended learning is utilised for all programs in the university. This study aims to investigate blended learning approach in language teaching during the Covid-19 pandemic through the perspectives of English teachers at the National Economics University. The data collected from an online survey with English teachers in the Faculty of Foreign Languages, NEU are used to explore (1) how English teachers are adapted to the new teaching method, (2) how they organize live online classes, (3) the benefits and challenges which blended learning approach bring, (4) how effective the blended learning approach is in language teaching and learning. It is expected that the pandemic will not end soon and blended learning still continue in the future, so the study will also suggest recommendations to improve the effectiveness of blended learning environment.