Abstract: Provided are a crystalline form of a compound represented by formula A, the crystalline form being crystalline form I, crystalline form II, crystalline form III, crystalline form IV, crystalline form V, crystalline form VI, crystalline form VII, crystalline form VIII or crystalline form IX, a preparation method therefor, a composition thereof, and an application thereof in the preparation of a P2X3 receptor antagonist or an application thereof in the preparation of drugs preventing and/or treating pains, urinary tract illness or respiratory system illness. The compound has high P2X3 antagonist activity, and has good selectivity, low toxicity, good metabolic stability and little taste influence.