As a highly complex integrated system, aircraft structural integrity remains a critical objective in the aerospace industry. The load spectra serve as a key linking operational missions, load transmission, structural responses, and damage evolution. Its accuracy and representativeness directly determine the reliability of structural integrity assessments. This paper comprehensively reviews recent advances in aircraft load spectrum research both domestically and internationally, with a focus on its essential role within structural integrity frameworks, innovations in measurement technologies, cutting-edge methods for multi-source data fusion and intelligent processing, and their practical engineering applications, aiming to provide theoretical support and technical references for structural integrity design, service life management of aircraft in future, and effective implementation of Structural Integrity Programs in terms of load spectrum data acquisition.