Over the last ten years, continuous attention has been paid to the use of digital games in vocabulary learning. Their effectiveness and availability have been widely discussed. However, the experiences of language learners and the underlying patterns of their engagement while using digital games for vocabulary learning remain underexplored. In order to fill this significant gap, this study aimed to examine the influential mechanism of English as a Foreign Language (EFL) learners' flow experiences in digital game-based vocabulary learning (DGBVL). The sample consisted of 306 Chinese EFL learners who had DGBVL app usage experience, and data collection was based on a DGBVL flow experience instrument employed through an online platform. Structural equation modeling (SEM) was employed to assess the reliability and validation of the existing scale for various DGBVL apps. A multi-group analysis was then conducted, revealing that the influential mechanism was a process in which the effects of antecedents on outcomes could be mediated by flow experiences. In addition, the role of usage frequency was also explored, and three paths were found to differ across three usage frequency levels (i.e., seldom, sometimes, and always): the effect of balance of skill and challenge on enjoyment, the effect of enjoyment on satisfaction, and the effect of perceived learning on satisfaction. These findings provide new insights for the influential mechanism of flow experiences and will assist EFL learners in optimizing their learning outcomes in digital game-based vocabulary learning.