Reading is the meaningful interpretation of printed or written verbal symbols. The importance of reading in EFL teaching and learning has been acknowledged. According to schema theory, background knowledge has a significant effect on reading comprehension. As academic knowledge is part of background knowledge, an EFL student’s knowledge of a particular academic field would affect his performance on tests of reading comprehension.This thesis reports on an experimental study carried out to explore the effect of academic background on EFL reading comprehension in a Chinese context. The subjects were 76 first-year postgraduates from College of Law, College of Mechanical and Energy Engineering, College of Economics and College of Life Sciences at Zhejiang University. They were tested with four passages based on their four different subject areas. The results reveal that students reading passages related to their area of study would perform better than students unfamiliar with that subject.Meanwhile, the role of EFL language proficiency in reading comprehension has also been examined. Language proficiency of the subjects was divided into different levels according to their scores of the Graduate Admission Test of English. Two "linguistic thresholds" were found in the effect of academic knowledge on EFL reading comprehension performance. For low proficiency students there was a threshold below which they did not have the linguistic capacity to make use of their background knowledge. For advanced students, there was also a threshold above which they were so proficient linguistically that they could compensate for lack of background knowledge by making full use of their language resources.