The present disclosure provides crystalline form A of 3-(6-(1-(2, 2-difluorobenzo [d] [1, 3] dioxol-5-yl) cyclopropanecarboxamido)-3-methylpyridin-2-yl) benzoic acid and process of preparation thereof. The crystalline form A has low hygroscopicity, good stability, is convenient to store. It has higher solubility than that of prior art and therefore plays an important role in further optimization and development of the drug.