Abstract: Non-side-looking airborne radar can induce variation of clutter signature with range and the conventional method for space time adaptive processing has significant performance degradation. To deal with this problem, this paper presents an adaptive subspace method. Firstly, the geometry parameter is estimated by curve fitting. Then the clutter subspace can be represented using the estimated geometry parameter. Finally, data is projected on the orthogonal complement subspace of clutter to suppress the clutter. The simulation results illustrate that the method is able to obtain an accurate estimate of the parameters and a good clutter suppression performance.