Previous neuroimaging studies used functional magnetic resonance imaging (fMRI) to clarify the different brain activities when bilingual speaker comprehend their first language (Ll) compared with their second language (L2). Many studies show the different activation patterns of alphabetic language and logographic language. It is unclear that if bilinguals̀Ll and L2 language are all logographic language (e.g. Chinese and Japanese), whether Japanese (L2) processing is different from Chinese (Ll) for bilinguals' brain activity. To study the underlying mechanisms, we used functional magnetic resonance imaging (fMRI) to visualize Chinese-Japanese bilinguals' brain activity in both of Chinese character and Japanese Kanji. Precuneus were activated by morphology judgment in Chinese word contrast with Japanese word. The results with Chinese and Japanese logographs suggested precuneus were played an important role in Chinese morphology processing for Chinese-Japanese bilingual speakers.