CBI (Content Based Instruction) teaching is to transform a single language skill teaching method into a teaching method that integrates content and language as a whole. The main aim of this research is to know the actual implementation of the CBI model in university English classrooms in mainland China through scientific research methods. It will look at the perceived effectiveness of the CBI model and the challenges of implementing the CBI model. Based on the research purpose, this research explores the following research questions: how much students and teachers understand the basic concepts of CBI; the benefits and challenges of implementing CBI teaching methods in university English classrooms in mainland China. A review of selected literature briefly examines Input Hypothesis and Zone of Proximal Development. The data comes from questionnaires and in-depth interviews. The results seem to show that CBI can effectively improve students' English level, but there are many problems in the specific implementation process. The evaluation of CBI pedagogy needs to start from the perspective of teachers and students. It also emphasized the importance of the basic concepts of CBI. This research will help those students and teachers in the Chinese universities who would like to adopt CBI model and also the people who want to know the real situation of CBI model in the English classroom in China universities.