Interface, Interaction and User Experience Design Collaborative Aid Mobile Application by Pengfei Wang 17.5 million people die of sudden cardiac death every year. This application allows users to call people nearby rather than distant hospital for first-aid, and get guidance for accident witnesses to perform first-aid to victim before others arrive, which helps to shorten rescue time. It also encourages users who lack first-aid knowledge to get free training and help victims. To make it easier for users to start, the interaction design of this app is simple and straightforward. The design concept is based on collaborative work, which propose an efficient possibility to handle sudden death.