An automatic working system comprises a self-moving device moving and working in a working region, a handheld device and a control module. The handheld device is configured to move along a perimeter of the working region with a user and comprises a detecting module, detecting the perimeter information of the working region; and an input module, receiving a command of the user for detecting the perimeter information. The control module comprises a perimeter setting unit, generating virtual data of the perimeter, an area calculation unit calculating the area of the working region and a scheduling unit generating a working schedule. The self-moving device comprises a working module, a driving module and a controller. The controller controls the self-moving device to work according to the working schedule.