We use the ~370 square degrees data from MWISP CO survey to study vertical distribution of molecular clouds (MCs) toward tangent points in region l=[16,52]deg and |b|<5.1deg. The disk consists two components with layer thickness (FWHM) ~85pc ~280pc, respectively. In inner Galaxy, mass thin is dominant, while traced by discrete MCs weak emission thick probably <10% whole disk. For gas disk, we i...
