Abstract: This paper mainly studies the fuzzy fractal characteristic of sea clutter as well as the application of fuzzy fractal theory in radar lowobservable target detection.Fuzzy fractal theory is proposed based on the concept merging fuzzy theory and fractal theory.The two important concepts of it are the local fuzzy fractal dimension (LFFD) and the local grade of fractality (LGF).The fuzzy concept of fractality of sea clutter can be reconstructed as an fuzzyattribution,i.e. a kind of fuzzy set,which is equivalent to “grade” defined well in fuzzy theory.The local fuzzy fractal dimension and the local grade of fractality are for short-time sea clutter series,and sliding measurement can be used for dealing with long-time sea clutter series.By the verification of X-band real sea clutter,the method proposed has a good performance of detecting low-observable target in sea clutter.