Abstract: As user touch experience is mostly affect by users'ability and devices'capacity, the customized touch-friendly interface tailored to customer and device is demanded to provide better user experience.Therefore, we propose a method to create adaptive user interface incorporating touchfriendly size.Firstly, in order to overcome the difficulty of small size target, Fitts's formula is modified so that it can be employed to calculate the touch-friendly size with user and devices information.Then, an Android application is layout as a case study to present the method and procedures of computing touch-friendly size.In our proposed interface, the program performs an initial test as to obtain the information of users and devices as the users firstly operate on mobile phone, after which the touch-friendly size can be optimized.As users may change their operating behavior afterwards, verification tests are necessary to update information before each use, and so the optimaltouch-friendly size is revised each often.In the end, the user interface is modified according to the optimal touch-friendly size.Our experiment and users'test results indicate that adaptive user interface can effectively save task completion time and improve users'experience.