Abstract: By adding sodium fluoride in invalid phosphoric-based acid polishing solution to prepare high molecular ratio cryolite via sodium fluoride reaction with Al3+ from invalid phosphoric-based acid polishing solution.Results indicated that，with reaction temperature of 60 ℃，reaction time of 40 min，n(NaF)∶n(Al)=1.3，sedimentation time was 1.5 d，aluminum removal rate was 98.6%.The cryolite molecular ratio of NaF to AlF₃ is 3.81.The production process not only recycled the polishing liquid，and production process is simple，cryolite has high molecular ratio and yield rate.It has good application prospect.

Key words: Invalid phosphoric-based acid polishing solution, Sodium fluoride, High molecular ratio cryolite, Precipitation