This study was aimed at identifying failure mechanism and strength of brazed copper pipe used in household air conditioner. For these ends, the brazed joints with various brazing length were manufactured according to manufacturer’s recommended methods. The 3-dimensional X-ray technique was used to identify internal flaws and their failure mechanism in brazed joints. And, strength of brazed joint was evaluated by static tests. To evaluate the effect of heat on the brazed joints, the micro-Vickers hardness is measured. Also, bursting tests were performed for burst pressure of brazed joints by using of self-designed internal pressure bursting tester.