With the development of construction industry at home and abroad, construction projects in medium and large cities are developing towards higher lifting heights and smaller operating spaces. The level of internal climbing tower cranes is also increasing, and the difficulty of dismantling internal climbing towers is also increasing. The portable tower crane has no tower and can be directly installed on the top of roof. It can be used to dismantle the internal climbing tower crane, and is easy and safe to operate. The form of portable tower crane jib luffing is more suitable for conditions where the buildings roof space is small. By using jib luffing, obstacles can be effectively avoided and the internal climbing tower crane can be easily disassembled.