The aim of present paper is to experimentally investigate the dynamic strength characteristics of LNG cargo containment system under impact loads. A series of impact tests for full-scale MARK III insulation system is undertaken using a custom-built drop test facility as varying height and weight of the drop object. Based on a series of repeated drop tests, displacement recovery was measured for the assessment of damping characteristic of insulation system. Crack initiation was also measured during the cyclic drop test. The quantitative relationship between impact load and crack initiation as well as the crack propagation with respect to drop number are derived.