This study investigates the accuracy of solution for fractional-order an SEIR epidemic model by using the homotopy analysis method. The homotopy analysis method provides us with a simple way to adjust and control the convergence region of the series solution by introducing an auxiliary parameter. Mathematical modeling of the problem leads to a system of nonlinear fractional differential equations. Indeed, we find the analytical solution of the proposed model by Homotopy analysis method which is one of the best methods for finding the solution of the nonlinear problem. Numerical simulations are given to illustrate the validity of the proposed results.