An example method includes displaying a first interface image. The first interface image is encoded to obtain encoded data of the first interface image. Encoded information of the first interface image is sent to the second electronic device. An ith frame of interface image is displayed in response to an update operation on the first interface image. N difference regions in the ith frame of interface image compared with an (i−1)th frame of interface image are obtained. If an area proportion of the N difference regions in the ith frame of interface image is less than a preset value, image content of the N difference regions is encoded to obtain first encoded data. First encoded information is sent to the second electronic device, where the first encoded information includes the first encoded data and location information of the N difference regions in the ith frame of interface image.