L-PROLINE compound, its monohydrate and the crystal of a kind of white 2 inhibitor of sodium glucose co-transporter 2 are provided. Specifically, 1,6- dehydration -1-C- { the chloro- 3- of 4- [(the fluoro- 4- ethoxyphenyl of 3-) methyl] phenyl } -5-C- (methylol)-β-L- Chinese mugwort Du pyranose L-PROLINE (formula (I) compound), its monohydrate, the crystallization of A type and preparation method thereof are provided. The A type crystallization of acquired formula (I) compound has good chemical stability and stability of crystal form, Bing and recrystallisation solvent low toxicity and low residue used, can preferably use what clinical treatment.提供一種鈉‑葡萄糖協同轉運蛋白2抑制劑的L‑脯氨酸複合物、其一水合物及晶體。具體地，提供1,6‑脫水‑1‑C‑{4‑氯‑3‑[(3‑氟‑4‑乙氧苯基)甲基]苯基}‑5‑C‑(羥甲基)‑β‑L‑艾杜吡喃糖L‑脯氨酸(式(I)複合物)、其一水合物、A型結晶及其製備方法。所得到式(I)複合物的A型結晶具備良好的化學穩定性和晶型穩定性，幷且所用結晶溶劑低毒低殘留，可更好地用於臨床治療。
