A method and device for simulating microstructure evolution of a material based on solution in an exponential time-difference format. The method includes: establishing a reaction rate theory model for substance defects, wherein the model is expressed with equations that comprise linear terms having coefficients characterized with matrixes; and iteratively solving the equations by using an exponential time-difference format, wherein during the iterative solving, the linear terms with exponential powers of the matrixes as the coefficients are integrated. Since a rate theory is not limited by spatial-temporal scales, the advantages of the rate theory can be significantly reflected when the microstructure evolution is simulated under a high damage dose condition; and then, the equations are solved by using the exponential time-difference format, with a solved result better in accuracy and higher in precision.