The problems of this study that if there is any significant correlation between students’ lexical knowledge of collocation and their reading comprehension. The purpose of this study is to find out whether there is correlation between students’ lexical knowledge of collocation and their reading comprehension. Non-experimental quantitative research used by writer as the method. As the population, the second semester students of English Department of Teacher Training and Education Faculty of Syiah Kuala University were selected. By using purposive sampling technique, 20 students were taken as the sample. The data of this study were reading comprehension test and collocation test. Based on the calculation of the data, the sum of collocation mastery test score (∑X) and the sum of reading comprehension test score (∑Y) were high 1110 and 1475. The result of data analysis showed that the correlation coefficient (rxy) between two variables is 0.90. It means that Ho is rejected and Ha is accepted. In conclusion, there is significant correlation between students’ mastery in collocation and their achievement in reading comprehending at the second semester students of English Department of Teacher Training and Education Faculty of Syiah Kuala University 2014/2015 academic year.