The embodiment of the invention provides a remote sensing imaging simulation method and a device, which relate to the technical field of computer simulation and are used for simulating the imaging result of a satellite optical sensor. The method includes: acquiring a first image; Determining a downsampling region in the first image according to downsampling parameters and imaging mode parameters of the optical sensor; Performing down-sampling processing on pixels in the down-sampling area to obtain a second image; The second image is adjusted according to the imaging mode parameters to obtaina remote sensing imaging simulation image based on the imaging mode parameters. The method can simplify the simulation process of satellite remote sensing imaging and reduce the cost and difficulty ofsatellite remote sensing imaging simulation.