Abstract: A rotatable lamp assembly includes a base having a T-shaped through-hole extended in an axial direction and including a first through hole section having a relatively large diameter and a second through hole section having a relatively small diameter, a luminous tube disposed within the first through hole section; a head rotatably fitted within the second through hole section, and a resisting member disposed onto an inner wall of the first through hole section to resist against an end surface of the head.