Due to the particular structure of interference infrared imaging spectrometer, its online nonuniformity calibration and correction is always a difficult technical problem which has not been solved in engineering. Based on the in-depth analysis of principle and structure to the space-modulated interference infrared imaging spectrometer, an effective method of online nonuniformity calibration and correction was developed for this type spectrometer. The corresponding simulation model for the algorithm was given. The simulation results had shown the correctness and validity of the algorithm, which should make it possible for the on-orbit nonuniformity calibration and correction of spaceborne interference infrared imaging spectrometer.