With the bigger and bigger construction scale of wharves, ultra-large caissons come into being and gradually develop, which need the help of the crane barge in the process of launching and placing. Taking the ore terminal with a capacity of 400 000 DWT in Dongjiakou area of Qingdao port as an example, the paper demonstrates the launching and placing process of ultra large caissons of 6 000 t. The success of the project has provided reference for the launching and placing process of the ultra-large caissons.