Second language learners process aspectual mismatch between verbs and adverbs differently from native speakers (Long et al., in press). Then, what about mismatch between grammatical aspect and adverbs? We explore into this question using event-related potentials (ERP), and compare our results with aspectual mismatch study with L1 Chinese speakers reported by Zhang & Zhang (2008). Eleven Chinese speakers with high Japanese proficiency read Japanese sentences where aspectual property of adverbs either matched or mismatched with the progressive aspectual marker. Brain responses to mismatch were recorded by ERP. Our results showed that violations of grammatical aspect elicited a 300-500ms posterior and left central negativity, which reflect resolving incompatibility of aspectual markers. This negativity is similar in its timing and distribution to the negativity reported in Zhang & Zhang (2008) for native speakers. This suggests that Chinese learners of Japanese process grammatical aspect as they do in their native language.