The purpose of this study is to confirm the sequential mediating effect of optimism and resilience in the effect of college student’s social support on career preparation behavior. The research method was surveyed on 219 college students. In order to verify the research model, demographic analysis and Person’s correlation were analyzed using SPSS, and serial double mediating effect was verified using PROCESS Macro’s Model 6. First, social support, optimism, resilience, and career preparation behavior all showed statistically significant positive correlation. Second, it was found that social support showed that optimism and resilience had a statistically significant positive effect, but did not have a significant effect on career preparation behavior. Optimism was found to have a statistically significant positive effect on resilience and career preparation behavior, and resilience was found to have a statistically significant positive effect on career preparation behavior. Third, as a result of verifying the sequential mediating effect of optimism and resilience in the relationship between social support and career preparation behavior, the indirect effect was found to be significant. It is intended to provide educational and policy implications for improving college students’ career preparation behavior.