Provided is a lithography model simulation method. The method comprises receiving a first mask image, generating a second mask image by simulating an optical model on the first mask image, generating at least one third mask image by simulating a quenching model on the second mask image, and generating a resist image by performing machine learning on the first mask image, the second mask image, and the third mask image. The generating of the resist image comprises outputting first output data by convolving the first mask image with a first kernel, outputting second output data by convolving the second mask image with a second kernel, outputting third output data by convolving the third mask image with a third kernel, and adding together the first to third output data. Each of the first to third kernels is or includes a free-form kernel.