The purpose of this study was to investigate causal relationship among athletic identity, tenacity and grit of high-school taekwondo athletes. For this purpose, a sample of 300 drawn out of the high-school taekwondo athletes from Seoul, Gyeonggi area was selected as a population. Data acquired from 7 high-school taekwondo athletes were excluded due to inconsistency in their responses. Therefore, the data of 293 people was used for a final analysis. For the collected data, descriptive statistics, confirmatory factor analysis, correlation analysis, and structural equation analysis were performed using SPSS 23.0 and AMOS 23.0 programs. The following results. First, the athletic identity of high-school taekwondo athletes has a positive(+) effect on tenacity. second, the athletic identity of high-school taekwondo athletes has a positive(+) effect on grit. Third, the tenacity has a positive(+) effect on post-traumatic growth.