For adaptive content generation, it means that the application can recognize a user's preference and consequently retrieve and present the appropriate media objects stored in the databases. That is, the application presents only the media objects with the conditions evaluated to be true according to the user's demand or preference. The feature of adapting présentation contents can significantly improve browsing results through providing materials that are more suitable for each individual user. In the mobile environment, some more changing factors can affect a user's access to the contents generated by the presentation engine. These factors include location, available bandwidth, past visits, the currently closest media source, etc. In this paper, we propose an adaptive content generating engine called Mach for mobility-aware multimedia applications. Mach's goal is that a single content description file can be applied to compose various multimedia presentations. By following the statements of the description file and the user's preference, Mach can dynamically generate adaptive contents for each class of users. In this way, the content designer does not need to compose several description files for each class of users. Mach is based on the XML (eXtensible Markup Language) standard and thus its platform independence makes our work well-suited to the mobile environment.