A p-toluenesulfonate of MEK kinase inhibitor, its crystalline form and preparation method are disclosed. Specifically, 2‑((2‑fluoro‑4‑iodophenyl)amino)‑1‑methyl‑4‑((6‑picoline‑3‑yl)oxy)‑6‑carbonyl‑1 is disclosed , 6‑dihydropyridine‑3‑formamide p-toluenesulfonate (compound of formula (I)), its type I crystal and its preparation method. The obtained type I crystal of the compound of formula (I) has good crystal form stability and chemical stability, and the crystal solvent used has low toxicity and low residue, and can be better used in clinical treatment.一種MEK激酶抑制劑的對甲苯磺酸鹽、其結晶形式及製備方法被公開。具體地，公開了2‑((2‑氟‑4‑碘苯基)氨基)‑1‑甲基‑4‑((6‑甲基吡啶‑3‑基)氧基)‑6‑羰基‑1,6‑二氫吡啶‑3‑甲酰胺對甲苯磺酸鹽(式(I)化合物)、其I型結晶及其製備方法。所得到式(I)化合物的I型結晶具備良好的晶型穩定性和化學穩定性，並且所用結晶溶劑低毒低殘留，可更好地用於臨床治療。
