The mobile devices have been widely spread and become frequently used equipment in daily life. Besides, watching videos on these devices has become a more and more popular activity. However, there are several challenges (e.g., small mobile screen size, low bandwidth, fragmented watching time) hindering mobile video watching: they either interrupt the watching process or limit users to browse many contents at the same time. Traditional video summarization techniques are suffering the small screen issue. Therefore, we propose a system, Comp2Watch which is pronounced like “come to watch”. It implies the meaning of “composing the frames into a collage” and “compressing the watching time”. It puts ROI factors into consideration in order to help users take a quick glance at videos. Also, we modify the cost function to incorporate the templates with variable aspect ratios. We also address the monotone layout problem caused by the limited space. The experimental results show that users can obtain clearer subject without losing many contexts.