A basic assumption of most recently proposed waveform design algorithms is that the target impulse response is a known deterministic function or a stochastic process with a known power spectral density(PSD).However,it is well-known that a target impulse response is neither easily nor accurately obtained;besides it changes sharply with attitude angles.Both of the aforementioned cases complicate the waveform design process.In this paper,an adaptive robust waveform selection method for unknown target detection in clutter is proposed.The target impulse response is considered to be unknown but belongs to a known uncertainty set.An adaptive waveform library is devised by using a signal-to-clutter-plus-noise ratio(SCNR)-based optimal waveform design method.By applying the minimax robust waveform selection method,the optimal robust waveform is selected to ensure the lowest performance bound of the unknown target detection in clutter.Results show that the adaptive waveform library outperforms the predefined linear frequency modulation(LFM)waveform library on the SCNR bound. A basic assumption of most recently proposed waveform design algorithms is that the target impulse response is a known deterministic function or a stochastic process with a known power spectral density (PSD) .However, it is well-known that a target impulse response is neither easily nor distinguished obtained; besides it changes sharply with attitude angles ..Both of the cases cases of the waveform design process.In this paper, an adaptive robust waveform selection method for unknown target detection in clutter is proposed. The target impulse response is considered to be unknown but belongs to a known uncertainty set. An adaptive waveform library is devised by using a signal-to-clutter-plus-noise ratio (SCNR) -based optimal waveform design method.By applying the minimax robust waveform selection method, the optimal robust waveform is selected to ensure the lowest performance bound of the unknown target detection in clutter. Results show that the adaptive waveform library outperforms t he predefined linear frequency modulation (LFM) waveform library on the SCNR bound.