Preparation method of Risperdal I-type crystal

The invention provides a preparation method of Risperdal I-type crystal. The preparation method comprises following steps: 1) purification, wherein Risperdal crude product, water, ethanol, and an adsorbent are mixed at a ratio of 1:5-10:3-6:0.005-0.03, an obtained mixture is subjected to 1 to 2h of heating reflux at 60 to 85 DEG C with stirring, and the absorbent is removed via filtering before cooling; and 2) recrystallization, wherein an obtained filtrate is subjected to heating distillation for 3 to 6h at 75 to 85 DEG C so as to obtain recycled ethanol, and white crystal is obtained via precipitation from the filtrate, after distillation, an obtained solution is cooled to 10 to 30 DEG C gradually, and is subjected to thermal insulation for 4 to 8h, and the Risperdal I-type crystal is obtained via filtering, washing, and drying, wherein the cooling speed is controlled to be 5 DEG C/min. The used solvents are nontoxic, and are convenient to recycle, and purity of the obtained Risperdal I-type crystal is as high as 99.62%.