Abstract: A calibration method of fundamental frequency wavelength of space heterodyne spectrometer(SHS) is presented according to the operating principle of SHS and the generation mechanism of interferograms. Pixel phases along the normal direction of interferograms were calculated and linearly fitted to get the phase slopes corresponding to the space frequencies along the normal direction of interference fringes. When the phase slopes of laser interferograms for two known wavelengths were obtained, and then the fundamental frequency wavelength of the SHS was determined. The data test results of four groups of wavelengths show fundamental frequency wavelengths calibrated by this method have good consistency, and the standard deviation is 0.044 nm. In addition, the spectrum from simulated calibration results and that from actual measurement are consistent at a high degree, which implies the feasibility of the method.