The detection of video deepfake is an emerging task in computer vision that holds significant importance for internet content security. As deepfake technology advances and the proliferation of fake videos becomes more rampant, research on video deepfake detection techniques is particularly crucial. This paper begins by introducing representative algorithms for video deepfake and its detection, followed by a brief analysis. It then summarizes commonly used datasets, as well as related evaluation systems. Finally, it discusses the main challenges and future directions of video deepfake detection technologies.