Abstract :
The main purpose of this research is analyze the collocation on written test. The researcher analyses the data by identifying lexical collocation and collocation clash based on conventional theory, iWeb14 Billion Word Web Corpus and lexical collocation formula by Benson et al. The source of the data was students? answer for IELTS simulation Writing Task 1. There are three themes, these three tasks require the test takers to describe the data using language expression to describe trend and comparison. The result shows there are 74 lexical collocations and 37 collocations error found in task 1. This research revealed that collocation error caused by inter language error or interference from mother tongue which is the most happens by student and intra language error or overgeneralization.