|The aspect marker le is a central temporal marker in the Chinese tense-aspect system and is a complicated language element for L2 learners to acquire. Previous L2 studies have looked only at learners' production data and have generally concluded that English native speakers transfer the English past tense to Chinese aspect le (Zhao, 1996; Jin & Hendricks, 2003; Teng, 1999; Yang, 1999).My preliminary question is whether English native speakers transfer the English past tense to Chinese aspect marker le in their comprehension. For this question, I run a grammaticality judgment (GJ) task. In this task, I examine whether learners know that le can co-occur with future or present adverbials. The results suggest that English learners accept the concurrence and do not equate the past tense and le. This result argues against the previous claim. Then how do English learners interpret the verbal le? In present study I run three interpretation tests where the verbal le occurs in different contexts. In the first interpretation task, I examine how learners interpret the interaction of le and four kinds of verbs based on the classification of Vendler/Dowty. The results show that learners consistently interpret le as perfective even when it shows imperfective function concurring with some activities and statives. The explanation for it is that learners transfer the perfective function of English -ed to the verbal le and/or over generalize the perfective function of the verbal le. Based on GJ test and the first interpretation test, we understand that learners know that the verbal le is an aspect marker and they performed very well on the interaction of le and achievements/accomplishments in sentences with a single event. The second interpretation test is to investigate whether learners can integrate the temporal information for the interaction of le and achievements/accomplishments correctly in complex contexts. I give participants paired sentences with two successive events which were almost the same except one is past tense and the other is future tense. The second interpretation test is timed by Paradigm. An example is shown below. (a) Wo xie le xin yihou cai qu le gongyuan. (Past event) I write LE letter after then go LE park. I went to a park after I wrote the letter. (b) Wo xie le xin yihou zai qu gongyuan. (Future event) I write LE letter after then go park. I will go to a park after I write the letter. In these two sentences above, the tense of the first events is deduced from the tense of the second events. Due to the lack of this kind of deduction in English tenses, we predict learners will have difficulty on the temporal interpretation of the sentences with two events even though they can correctly interpret the interaction of le and achievements/accomplishments in single event; they will perform better for the past sentences than the future sentences due to both events in past sentences including le and consistently defaulting past tense. The results show that learners cannot distinguish the temporal difference between the two sentences and did poorly for both future and past sentences. An additional interesting result is that native speakers take longer to interpret future tense of sentence (b) than past tense of sentence (a). The explanation is that native speakers slow down in future tense due to the temporal information conflict in the first and second events. In the third timed interpretation task, I am interested in whether explicit temporal adverbs help learner's interpretation. They performed poorly on the combination of le and activities/statives in test 1, and on the sentences with two events in test 2. So the sentences in this test add temporal words in sentences on which they did poorly. The results show that temporal words help a lot in learners' interpretation and native speakers' processing of the verbal le. The possible explanation is that the temporal words give subjects clear time reference like English tense markers and overwhelm the temporal integration required by the aspect marker le.In short, this paper describes and tries to explain some interesting phenomena in interpretation and processing of the aspect marker le which have not been investigated previously. This study shows much broader factors of L1 influence and supports that the temporal semantic information affects sentence processing. Consequently, my study will contribute to the understanding of interpretation in second language acquisition as well as semantic processing.