This study conducts a user-centered experiment on the touchscreen mobile device and the desktop computer with two popular e-book systems. 48 Taiwanese college students are recruited to perform 5 experimental tasks. The experimental results show the touchscreen mobile device is intuitive for the mobile users to read e-books as compared to the desktop computer. But, interestingly, they prefer to read e-books page by page as reading a traditional physical book. Furthermore, the results indicate the reading performance on the touchscreen mobile device could be compromised by the poor interface design (e.g. ‘Memory Retrieval’ and ‘Search’ functions) of the e-book system. This study suggests the ‘virtual keyboard’ on the touchscreen should be improved and taken into consideration for the new generation touchscreen mobile devices to satisfy their reading requirements.