The Goutoupo granite of Shuanggou belongs to the high SiO₂, K₂O peraluminous A2 type postorogenic (postcollision) Granite, formed in the extension structural setting (crust thickness <15 km. According to the U-Pb dating of zircon, the age of Shuanggou rock body is (235.4±1.4) Ma. In combination with the regional geological information, the emplacement period and geochemical nature of Shuanggou rock body show that the Jinshajing—Ailaoshan ocean basin was closed before T2 final period, the collision orogeny was ended, the postorogenic extension stage began under the collapse mechanism of orogene in the study area.