With the development of mobile devices, researchers pay more and more attention to application software based on it. Currently, most animation making software is oriented for professional people, which are tedious and complex on operation. It is difficult for novices to understand the making animation process. Aimed at removing the complexity barrier and allowing nonprofessional users to create a wide variety of animations quickly, this paper proposes a sketching animation system. Besides of basic action editing, we also focus on animation synchronization which is crucial in making animation. Experiments show that the time of making animation has been reduced. In addition, for the sake of making users have better experience in creating animation at all times and places, the system design pattern and interaction way have been improved based on pen in order to be used in any running platform. Especially for mobile devices, the easy-extended system architecture and pen-based interaction way are approved by users. Simplifying the making animation process has been proved to be able to reduce users' cognitive burden effectively.