Disclosure is related to a method and a system for intelligent defect classification and sampling, and a computer-readable storage device. The computer-implemented method acquires in-line defect inspection file, and retrieves the defect patterns over a device under test, e.g. a wafer from a fab. The system incorporates a defect pattern recognition engine to recognize the defect signature patterns from the defect patterns. A sampling scheme is performed to acquire weak defect patterns. A critical area analysis based on failure probability of weak patterns is incorporated to performing the sampling. The defect layout pattern groups probably causing the open or short failure can be obtained. The defect signature patterns through sampling are then displayed using a browsing system. Through a user interface, the user can perform functions, such as filtering, selection and merging, onto the defect patterns.