Thermal sprayed aluminum coating blisters were observed during the fabrication in a liquefied natural gas project，in order to identify the reason of blisters，field investigation and macro inspection were launched on the location distribution and appearance of the blisters，high-power microscope was used to observe the microscopic surface status of TSA coating. The blisters were damaged with a sharp knife，and the corrosion products and morphology of the bottom of the bubble shell were analyzed by energy dispersing analyzer（EDS）and scanning electron microscopy（SEM）. Environmental chamber was used to simulate the process of TSA blisters. The results showed that the coating of unsealed hot spray aluminum coating with non-breathable material for a long time could lead to rapid blister in the high temperature and high humidity environment. Based on the results，improvement measures and suggestions had been proposed for the construction control of thermal sprayed aluminum coating.