The present invention provides a hydrobromate of methyl 3-[(4S)-8-bromo-1-methyl-6-(2-pyridyl)-4H-imidazole[1,2-a][1,4]benzodiazepine-4-yl]propionate and related crystal forms and preparation method and use thereof. The hydrobromate has an excellent solubility (greater than 100 mg/ml), which is significantly superior to other currently commercially available or developed salt products of the compound, and the hydrobromate is particularly suitable for the preparation of injections, has relatively good stability under various crystal forms, and has good practical value and market prospects.本發明提供了3-[(4s)-8-溴-1-甲基-6-（2-吡啶基）-4H-咪唑[1,2-a][1,4]苯並二氮雜䓬-4-基]丙酸甲酯的氫溴酸鹽及其相關晶型與製備方法和用途。該氫溴酸鹽，溶解度極佳（＞100mg/ml），顯著優於該化合物當前各市售或研發的其他鹽類產品，尤其適合注射劑的製備，並且各種晶型形式下的穩定性也相對較好，具有良好的實用價值和市場前景。
