A screen update method includes identifying image resource data associated with a first image update event from a basic recording space in case that the first image update event occurs; loading the identified image resource data in a buffer space including a plurality of buffers, in which the image resource data are loaded in rotation on the buffer by a frame, respectively; sequentially determining the image resource data loaded on the buffer for each buffer, rendering the determined image resource data, and generating a first image at a first frame rate; generating a second image associated with a second image update event at a second frame rate in case that the second image update event occurs; compositing the first image with the second image to generate an entire image; and displaying the entire image on a display means.