Abstract: A process of the use of sodium sulfite heptahydrate as raw material，through dissolution，adding sulfur to produce sodium thiosulfate was researched.The mass fraction of the product was more than 98.0%，in line with the first grade requirements of Industrial Sodium Thiosulfate，HG/T 2328—2006.The process had many advantages，such as low production cost， easy-to-operate，and high economic benefit. It not only expanded the scope of sodium sulfite heptahydrate application，but also met the market demand.Therefore，it was appropriate for promotion.

Key words: sodium sulfite heptahydrate, sulfur, sodium thiosulfate