Li, Y., Li, Z., Zhang, K. and Lin, Y., 2016. Frequency-domain full waveform inversion with rugged free surface based on variable grid finite-difference method. Journal of Seismic Exploration, 25: 543-559. Full waveform inversion (FWI) is a challenging data-fitting procedure to solve model parameter reconstruction problems. But FWI with irregular topography, which is common in the real land cases, has been barely researched. For more accurately describing of the subsurface structures, we introduce the effect of surface topography in the full waveform inversion. Then we develop a frequency-domain modeling algorithm for irregular topography medium, and incorporate it into a full waveform inversion algorithm. The variable grid finite-difference method is applied to the frequency-domain modeling and inversion algorithm to improve the accuracy of results. Specifically, the computational domain near the surface is discretized by fine rectangular grids, while the rest part is discretized by coarse grids. We apply successive inversions of overlapping frequency groups and layer stripping strategy implemented with complex frequencies to the FWI algorithm to improve the stability of the iterative procedure. In the meantime, the pseudo-Hessian matrix is used to scale the gradient to improve the efficiency. In the numerical tests, we validated our algorithm with two synthetic tests consisting of a layered model and a modified dip section of the overthrust model.