Founded on the componential model of reading, Nation＇s construct of vocabulary breadth test and structuralists＇ view of syntactic knowledge, this paper attempts to investigate the relative significance of vocabulary breadth and syntactic knowledge in the prediction of Chinese EFL learners＇ reading comprehension test performance and whether the relative significance is moderated by the learners＇ different L2 proficiency. An experiment including three tests was carried out with 68 sophomores in Anhui Medical University. The findings show that： 1） there is a positive linear correlation between the learners＇ performance on a reading comprehension test and their vocabulary breadth and syntactic knowledge, with the multiple r being 0.551; 2） syntactic knowledge outperforms vocabulary breadth in predictive power and emerges as the stronger predictor of reading comprehension test performance; and the relative significance of syntactic knowledge over vocabulary breadth in the prediction of reading comprehension does not change with the EFL learners＇ L2 proficiency. The findings of this study provide implications for both reading instruction and remediation of learners＇ reading problems.
