This　letter　describes　an　attenuation　tomography　method　via　variations　in　the　envelope　peak　instantaneous　frequencies　(EPIFs)　of　seismic　signals.　For　a　linear　frequency-attenuation　model,　assuming　that　the　propagating　wavelet　can　be　modeled　by　a　Gaussian　function　with　constant　phase,　an　imaging　formula　using　EPIF　variation　is　derived.　In　tomography,　the　simultaneous　iterative　reconstruction　technique　(SIRT)　with　travel-time　weighting　is　proposed　for　tomographic　inversion.　Numerical　simulations　of　both　noise-free　and　noise-added　data　show　the　validity　of　attenuation　tomography　from　EPIF　variation.　SIRT　with　travel-time　weighting　yields　a　better　reconstruction　and　lower　residual.