High-frequency(HF) skywave over-the-horizon radar(OTHR) looks down its targets from the ionosphere

it has a large operating range and a large cover areas

but it also receives strong backscatterer echoes from the terrain and sea

and interference

such as radio frequency interference

industrial interference

impulsive noise

lightning impulsive

meteor trail echoes and so on.Interference can be divided into long time interference and transient interference.Transient interference lasts a short time

but its intensity is great.This paper first discusses the character of transient interference

then discusses its excision method

finally the method has been successfully applied to the real data from China experimental OTHR.The transient interference excision method is:first eigen-decomposition is used to separate the sea clutter subspace and filter it or ground clutter is filtered in frequency domain directly

then the transient interference can be detected

after that the original echoes with existing transient interference are excised

finally the excised clutter and target echoes are predicted by Burg linear prediction algorithm.