Expanded washing powder and its production method relate to the technical field of washing daily necessities, and consist of sulfonic acid 10- 15%, pentasodium 20- 10%, magnesium sulfate 14.7-48.4%, sodium carbonate 30-5% and sodium sulfate 22-20%. 0. 1% essence is mixed and stirred at normal temperature and pressure for 15 ~ 25 minutes to realize solid phase neutralization and molding, thus forming expanded washing powder products with bonding and polymerization functions. It is suitable for washing sweat, oil stain or dirt of various cotton, hemp, wool chemical fiber, silk, natural fabric and other objects, and has the advantages of simple process, less investment, low cost and strong detergency.