Abstract：On the basis of 1∶250 000 mapping of the Boindoi Sheet and Comai Sheet, the time-space structure and evolution of the arc-basin system on the southern side of the Bangong Co-Nujiang junction zone is analyzed by using the archipelagic arc orogeny model. The authors believe that during the Middle-Late Jurassic and Early Cretaceous an archipelagic arc-basin system formed on the southern side of the Bangong Co-Nujiang ocean concomitantly with its southward subduction and extinction, and that during the late Early Cretaceous to Late Cretaceous the arc-basin system evolution on the southern side of the Bangong Co-Nujiang junction zone ended through remnant sea basin sedimentation, closing and subduction, and subsequent collisional orogeny.