Abstract: The visualization experiment was built up to record the bubbles bursting at a free water surface with a high speed video camera for the whole process. The whole process could be divided into following successive stages: A floating bubble, the drainage of the liquid film, the puncture of the bubble cap, the film rolling-up and the liquid ring formed with the hole expanding, fine film drops emission under the effect of destabilization of a Rayleigh type. The punctured position and the film rolling speed of the bursting bubble, which were both important parameters for the dynamics of the film drop formation, were obtained by the subsequent image processing. The results of 137 bubbles with 2.18 mm curvature radius range, shows that the puncture mainly happens at the foot of the bubble, while a few bubbles indeed begin bursting at the top or in the middle of the bubble cap. The expression correlating the bubble curvature radius with the film rolling speed is obtained by fitting the data with the bubble radius ranging from 7 mm to 28 mm.