The key to guarantee the quality of English teaching in China is to understand and grasp the effect of the amount of explicit instruction on syntactic grammar on Chinese learners ’ability to deal with English complex sentences． This study is to investigate the relationship between amount of explicit syntactic instruction and the ability to comprehend four types of complex English sentences． ，based on questionnaire and reading comprehension test on 60 Chinese students of English as a L2 with differ- ent amount of explicit syntactic instruction and 20 native-English speakers． It is found that more explicit instruction on syntactic grammar may result in higher accurate comprehension and good performance in plausibility judgment ，which is equivalent to n- ative English speakers ，but poor performance in sentence complexity judgment． In addition ，Chinese students with different a- mount of explicit instruction on syntactic grammar are also different in using syntactic and semantic information in complex L2 English sentence processing． On the basis of these findings ，the theoretical value and implications are discussed at the end of the paper．