The invention provides a detection device for detecting status of optical disk, comprising: a blank detector used for detecting blank regions of optical disk so as to generate a blank-detected signal; an edge detector which is coupled to the black detector and used for detecting the conversion of the blank-detected signal so as to generate an edge-detected signal; a control circuit used for responding to the edge-detected signal and outputting a first control signal; and a defect detector which responds to the first control signal for detecting defect regions of the optical disk so as to generate a defect-detected signal. The detection device for detecting status of optical disk and related method may adjust the output or detecting mechanism of the defect detector according to detection result of the blank detector, and adjust the output or detecting mechanism of the blank detector according to detection result of the defect detector, thereby improving accuracy of digitally decoding of the optical disk drive system and enhancing stability of the system.