Domain knowledge is defined as the person's knowledge of a particular discipline, domain, or area that is relevant to the search [32]. Existing knowledge not only determmes users ability to understand the features and usage of an innovation [3], but also leads them into perceiving an innovation or a product similar to it to be less complex [42]. As a result, this research proposes that people who have solid knowledge in a particular discipline will understand the mobile digital library features. In addition, they will conduct better searches on a mobile digital library system