A radio link failure detection method of a user equipment transitioning between a Discontinuous Reception (DRX) mode and non-DRX mode cyclically in a wireless communication system includes transitioning between a Discontinuous Reception (DRX) mode and a non-DRX mode in a wireless communication system. The method also includes adjusting, when a mode transition occurs, a size of a monitoring window for a transitioned operation mode; reporting a radio channel condition acquired by monitoring and averaging the channel condition within the monitoring window; and repeating adjustment of the monitoring window size and report of the radio channel condition while moving the monitoring window as time progress.