Abstract: Introduced the method of preparing soda ash by double decomposition method with mirabilite and ammonium bicarbonate (solid).Mirabilite reacted with ammonium bicarbonate&nbsp; under the proper conditions to obtain sodium bicarbonate and mother liquor.Soda ash was obtained by calcining sodium bicarbonate.Ammonium sulphate was obtained by evaporating mother liquor.The product met the relative national standard.The factors influencing the quality of soda ash were obtained,and the feasible process conditions were confirmed:material mass ratio \[m(Na<SUB>2</SUB>SO<SUB>4</SUB>)∶m(NH<SUB>4</SUB>HCO<SUB>3</SUB>)\]was 1∶1.2;reaction temperature was 35~40 ℃;reaction time was 1 h;calcining temperature was 220~240 ℃;calcining time was 80 min,and evaporating temperature was 80 ℃.The mirabilite replaced the salt as the raw material in the technology,which made raw material utilization ratio high and production cost low.The technology is simple with less investment,higher profits,and no discharge of the three-wastes.&nbsp; <BR>