The Gaokao reform policies issued by the Chinese State Council in 2014 have been considered one of the most important policy changes in Chinese education in recent years. Shanghai, as one the two pilot regions for the new Gaokao reform, conducted the first round of new English Gaokao in January and June of 2017. This paper reports an empirical study that investigated the actual impact of the English Gaokao reform (the inclusion of Listening and Speaking component in particular)on teaching and learning of English in Shanghai high schools, in comparison to the expected washback effects by the policy makers, so that we may offer useful and practical suggestions to provinces and municipalities yet to start the reform. The results show that Shanghai English Gaokao reform has brought many positive washback effects, including the increased diversity and authenticity of teaching materials, more emphasis on the practice of communicative and integrated language skills in class. However, there are also negative washback effects, which are most notable in grade three classes: there are too many mock tests of the new item types in teaching materials, and too much teaching and practice of testtaking techniques. Differences of the washback effects are found among teachers of different age groups and years of teaching experience, and among students with different levels of English proficiency.