In this study, an optimal control strategy is applied to the SEIR (Susceptible-Exposed-Infected-Recovered) epidemic model with nonlinear transmission rate and time-delay caused by vaccination and antiviral treatment. This paper aims to recover the susceptible people by vaccination and treat the infected people by antiviral treatment. The susceptible and infected people are moved to the recovered group with a time delay. Pontryagin's maximum principle is used to obtain the optimal control inputs and the optimal time. Numerical results are consistent with the analytical ones and corroborate our theoretical results.