Tutorial videos of mobile apps have become a popular and compelling way for users to learn unfamiliar app features. To make the video accessible to the users, video creators always need to annotate the actions in the video, including what actions are performed and where to tap. However, this process can be time-consuming and labor-intensive. In this paper, we introduce a lightweight approach Video2Action, to automatically generate the action scenes and predict the action locations from the video by using image-processing and deep-learning methods. The automated experiments demonstrate the good performance of Video2Action in acquiring actions from the videos, and a user study shows the usefulness of our generated action cues in assisting video creators with action annotation.