Preparation method of erlotinib hydrochloride form B

The invention relates to a preparation method of erlotinib hydrochloride form B. The preparation method comprises following steps: free erlotinib base and an organic solvent are mixed so as to obtain a clear solution; hydrochloric acid is added dropwise into the solution; the mixture is heated for backflow, and then is cooled and filtered; and the residue is washed and dried so as to obtain erlotinib hydrochloride form B. Process technology of the preparation method is simple; crystallization velocity and purity are increased effectively; processes are stable, and operational feasibility is high; the preparation method is suitable for industrialized production; crystal form purity of the obtained products is high; and the products possess significant economic value.