Abstract: The study of bubble-bubble interaction has many valuableapplications in fields of fluid mechanics. But there are still manydifficulties in theoretical and numerical studies presently. Therefore,experiments using electronic spark to generate bubbles are designed in thispaper to investigate the interactions of two bubbles and bubbles with freesurface. The experiments are carefully controlled and the two bubbles aregenerated within 67\mus which can be considered as inphase. Manyphenomena can be found such as fusion, mushroom shape and split, jettingtoward, jetting direction change, jetting away and so on. Two feature parameters, dimensionlessdistance and period difference, are concluded to classify the phenomena oftwo inphase bubbles interaction, which aims to offer experimental referencesto the study of multi- bubble interactions.