To confirm the safety perfomance of LNG storage tank, the change in fracture toughness and within the X-grooved weld heat-affected zone (HAZ) of 9% Ni steel, which was SMAW and GTAW welded, was investigated. The weld metal specimens were prepared by taking the same weld procedure applied in actual LNG storage tank inner shell. All the tests were performed in the temperature ranging from room temperature to -162℃. The crack initiation fracture toughness was evaluated by performing the crack tip opening displacement (CTOD) tests. The lowest CTOD values were investigated and compared under different weld method.