A lithography method using a multiscale simulation includes estimating a shape of a virtual resist pattern for a selected resist based on a multiscale simulation; forming a test resist pattern by performing an exposure process on a layer formed of the selected resist; determining whether an error range between the test resist pattern and the virtual resist pattern is in an allowable range; and forming a resist pattern on a patterning object using the selected resist when the error range is in the allowable range. The multiscale simulation may use molecular scale simulation, quantum scale simulation, and a continuum scale simulation, and may model a unit lattice cell of the resist by mixing polymer chains, a photo-acid generator (PAG), and a quencher.