Background: Laser particle size analyzer has been widely used in drug production and research and development, and the test data of laser particle size analyzer is processed and stored by computers. On May 26, 2015, CFDA officially released one of the new appendices to the 2010 version of the GMP regulations, "Computerized Systems," which came into effect on December 1, 2015. The core content of Computerized Systems is as follows: - Requirements for Computerized System Validation - Data Compliance Requirements, including (A) Access Control, (B) Permission Settings, (C) Data Integrity, (D) Audit Traceability (Adjustable), (E) Electronic Signature (Non mandatory) - Electronic Data Security Requirements - Data Backup Requirements 2. Working Principle of Laser Particle Sizer Laser Diffraction Particle Sizer, commonly known as "Laser Particle Sizer", is a widely used particle size measurement device. Physical principles: diffraction of light/static light scattering. The scattered light spot presents a central bright spot with a series of concentric bright rings, known as the "Airy Spot". The distance from the center to the dark ring is called the radius of the Airy Spot. The larger the particles, the smaller the size of the Airy Spot.