Utilizing longitudinal data of 3477 students from 28 institutions, we examine the effects of structural diversity and quality of interracial relation on students' persistence towards graduation within six years. We utilize multilevel discrete-time survival analysis to account for the longitudinal persistence patterns as well as the nested structure of students within institutions. Compared with white students, African American and Latino/a students had much lower odds of persisting to graduation within six years. African American students had higher odds of persisting to graduation at institutions with higher percentage of underrepresented ethnic minorities. Similarly, Asian American students had higher odds of persisting to graduation at institutions with higher percentage of Asian students. For Latino/a students, their odds of persisting to graduation were higher at institutions where the perceived quality of interracial relation for Latino/a students was more positive. Our study also found that white students in our sample had lower odds of persisting to graduation at institutions with higher percentage of underrepresented ethnic minorities. Other important predictors that we included as control variables based on existing research were also found to be significant for our sample, including sex, parental education, high school GPA, number of advanced placement tests passed, institutional selectivity, college GPA, effort, and financial aid. We provided scholarly and practical implications based on these findings.