Studying mechanical behavior of rib cage in traffic accident, 1^<st>-6^<th> costal strains in the center of the inner surface was measured using the porcine thorax subjected to the impact load. The experimental setup applied free falling weight (m=21kg) was used, and falling height was set to 100mm and 200mm. Three specimens were used for each falling height and twice tests were conducted for one specimen. As the result of pectoral compression test, 2^<nd>-6^<th> ribs produced around from 1000 to 7000μ strain, and strain values clearly changed in each test condition. Especially, the maximum strain values in the second compression tests increased 10-30% in comparison with first ones. It is considered that the soft tissues around joints were lengthened. Consequently, thorax injury tolerance was influenced not only rib but joint strength of soft tissues.