TLR7 AGONIST CRYSTALLINE FORM A, PREPARATION METHOD AND USE THEREOF The present invention relates to crystalline form A of a TLR7 agonist 2-butoxy-7-(4-(pyrrolidin-1-ylmethyl)-benzyl)-5H-pyrrolo[3,2-d]pyrimidin-4-am ine (formula I), a method for preparing the crystalline form A, and the use thereof. NIL