Welding structures will be occurred sudden crack or failure by reduced fracture toughness in case of low temperature. To protect these unstable fracture is very important. Because fracture of welding part come from welding faults or residual stress, critical stress intensity factors are acquired at temperatures between $22^{circ}C$ and $-70^{circ}C$ from base metal, welding metal and H.A.Z. It was studied effectiveness of annealing and affection of residual stress under low temperatures. In case of fracture toughness test, it showed that fracture toughness value decreased, according to the decrease of temperature. Expecially In case that compressive residual stress was existed, $K_C$ increased.