A conversion method of applications of mobile devices is provided. The method includes the steps of obtaining a device feature information and a platform information of a mobile device, modifying, by a convertor, a first description data of a first application according to the obtained device feature information and platform information, and converting the modified first application to a second application in which the first application is represented by a platform-neutral language and at least includes the first description data for describing the interaction design of a user interface, and the second application is represented by a language corresponding to the platform information and can be executed on the mobile device.