This study aims to examine the acquisition of the Korean past tense '-eott-' and time adverbials in L2 Korean learners. To do this, this study used the longitudinal written texts of 6 Korean learners. The findings as follows. Firstly, the 6th week texts show the most errors in the usage of ‘-eott-’ in the final sentences; the 20th week texts show errors of relative time reference in coordinate and subordinate sentences; the 30th week texts show the most errors related to lexical aspect. Secondly, time adverbials are used more frequently in the early stages of acquisition. The learners used ‘-eott-’ more in the texts of the 20th and 30th weeks than in the 6th week. Finally, it seems safe to conclude that the function and role of time adverbials changes form tense-substitute to tense-reminder with longitudinal changes. (Yonsei University)