Abstract: The present disclosure relates to an in-store automatic payment method and system applied to an unmanned store service, wherein the method and the system reduce the burden of excessively collecting videos from a number of fixed cameras installed in the related art by using an egocentric video, computer computation overhead, and installation expense and operating expense of a system for an unmanned store. The method includes: collecting, by a mobile terminal, an egocentric video; detecting, by at least one among multiple devices, a purchase target item from the egocentric video; calculating, by at least one among the multiple devices, a level of reliability for the purchase target item from the egocentric video; and registering, by at least one among the multiple devices, the purchase target item on a selected-item list of a user when the level of reliability is equal to or greater than a preset threshold.