As a basic indicator of verbal ability, verbal fluency refers to the degree of fluency in the use of language to convey information. The different components of working memory play an important role in verbal fluency. The inhibiting control mechanism takes place during L2 production processing in bilinguals, which may affect their verbal fluency and distinguish them from native speakers. The participants of our study were 90 Tibetan-Chinese bilinguals and 30 native Chinese speakers. The study attempts to investigate the verbal fluency and cognitive mechanism of bilinguals' L2. The present study's results found L2 verbal fluency in Tibetan-Chinese bilinguals is significantly lower than that of native Chinese speakers. L2 verbal fluency has changed under the influence of their mother tongue, mainly manifested as its semantic fluency of L2 relying not only on the visuospatial sketchpad but also the phonological loop. Moreover, the processing of bilinguals' L2 is influenced by the processing mode of L1 in the verbal fluency task.