Broad objective of this lecture is to presentation on UI Design and Paper Prototyping. Generally prototyping is creating a scaled-down or incomplete version of the system to demonstrate or test areas of the system. paper prototyping is a means of usability testing where representative users perform tasks by reaching a paper version of any user interface. Paper prototyping is using for aids UI design, provides basis for testing, team-building and allows interaction with user to ensure satisfactio. Finally discuss on some methods of prototyping, UI screen and Paper prototyping exercise.