Technique for preparing posaconazole polymorph i

The present invention relates to a technique for preparing posaconazole polymorph I. Posaconazole is dissolved in a mixed solvent of an alcohol and an ester, is heated to 60-70°C and dissolved, is cooled to 15-25°C within 1 to 4 hours, undergoes recrystallization, and is then kept in insulation so as to obtain posaconazole polymorph I; the mass/volume ratio between the posaconazole and the mixed solvent is 1:4 to 1:20; the volume ratio between the alcohol and the ester in the mixed solvent is 1:2 to 1:30; during cooling, the mixed solution is first cooled to 35-45°C within the first and second hours, an antisolvent is added by dripping within 10 to 60 minutes, and the temperature is reduced to 15-25°C after dripping. The technique is easy to operate and suited for industrialization, and has a high production yield. The mixed solvent of the alcohol and the ester as well as the alkane or cycloalkane used are solvents of low toxicity among organic solvents and have high recovery rates. Posaconazole polymorph I can be stably obtained, and the obtained product can be rapidly dried.