Abstract: Single structural parts are widely used in the structure of　modern aircraft, and this leads to mostly adopt components in aircraft assembly fixtures to locate product joints and process holes. Each of these components usually consists of a working part and a standard joint locator. In order to decrease the time, fixtures begin to be designed with CAD techniques, including the development and application of fixture-specialized design system. So automating the design of locators is very important to further increase the fixture design efficiency. Selecting and creating a standard joint locator is most costly during the design of a locator with a CAD system. Some new concepts, such as possible locating area, are defined firstly. Based on these concepts, an algorithm to autonomously select and create a standard joint locator is proposed. This algorithm has already been applied to develop the module "automatic design of joint locators" in the FixCAD system.