A heuristic finger detection method based on a depth image is disclosed. The method includes the steps of: acquiring a hand connected region from a user's depth image; calculating the central point of the hand connected region; calculating a plurality of extremely far points in the hand connected region that have extremum 3D geodesic distances from the central point; detecting fingertips and finger regions from the plurality of calculated extremely far points; and outputting fingertip positions and the finger regions. The method calculates and detects fingertips of users by means of 3D geodesic distance, without extracting boundary contours of hand regions, which improves robustness of gesture detection and reduces detection error rates. The method has the advantages of higher finger detection accuracy and fast computing speed.