This application discloses screen projection methods and systems and related apparatuses. In an example method, a first electronic device may send first display data corresponding to a first screen projection window on a second electronic device and second display data corresponding to a second screen projection window on the second electronic device to the second electronic device. The first electronic device may further send third display data and fourth display data to the second electronic device. In response to determining that the third display data is different from the first display data and that the fourth display data is the same as the second display data, the second electronic device may render and display a third screen projection page in the first screen projection window based on the third display data and display a buffered second screen projection page in the second screen projection window.