Abstract: Wave propagation in irregular topography and inhomogeneous medium environment can be calculated via split step Fourier Transform algorithm, the inverse parabolic equation method could locate the source position in complex environments effectively, however, directly extending this algorithm to the field of active radar target detection will meet several difficulties, the inhomogeneous medium will seriously deteriorate the quality of radar echo, leading to detection signals submerged in the noise from the background of clutter echo. In order to eliminate the influence of background scattering and improve the positioning accuracy, a novel adaptive elimination algorithm is proposed. This article combines the two-way parabolic equation method, adaptive interference cancellation algorithm and inverse parabolic equation, the combined algorithm have the ability to eliminate the background clutter echo effectively and locate the unknown or non-cooperation target accurately, and it can be validated by numerical simulation.