Video subtitles have become an increasingly popular foreign language learning tool, but their effectiveness in facilitating incidental vocabulary acquisition among Chinese university students has not been extensively studied. In order to investigate the effect of video subtitles on incidental vocabulary acquisition, a quantitative research was conducted with 90 Chinese university students. The research used an experimental research design in which participants were randomly divided into three groups: a no subtitle group, a Chinese subtitles group and an English subtitles group. Each group watched the same videos and completed pre-test and post-test vocabulary assessments to measure their incidental vocabulary acquisition. The results showed that both subtitled groups significantly increased vocabulary compared to the group without subtitles. In addition, the English subtitle group had the most significant effect, suggesting that English subtitles may be the most effective type for incidental vocabulary learning among Chinese university students. These findings have important implications for foreign language education in China, as they suggest that including video subtitles, especially English subtitles, can effectively enhance incidental vocabulary learning. Furthermore, the research’s use of an experimental research design strengthens the evidence supporting the effectiveness of video subtitling in language learning. Future research could further investigate the factors that influence the effectiveness of different types of subtitles on vocabulary learning, e.g., dual subtitles and keyword subtitles. In addition, exploring the effects of video with subtitles on other language skills (e.g., listening and pronunciation) is also worth considering.