The present invention is applicable to the field of communications technologies, and provides an in-synchronization and out-of-synchronization handling method and apparatus. The method includes: reporting, by a physical layer, an invalid frame indication to a high layer, where the invalid frame indication is used to indicate an invalid frame, and the invalid frame is a frame not used for detecting out-of-synchronization, so as to count the number of frames that are assured to be out of synchronization within timing; and when the number of frames that are assured to be out of synchronization within the timing reaches a predefined value, determining that a radio link is out of synchronization. By using the present invention, the modified timing of the timer and the number of in-synchronization indications correspond to each other.