Adopting the model of fractional Brownian motion, this paper presents the method of deducing Hurst exponent based on the observed sea clutter of S-band radar. Secondly the prediction technology of chaotic time series is studied based on memory-based predictor. Furthermore, adopting the method of support vector machine classifiers of the improved radial basis kernel function, this paper proposes a novel method of target detection based on the sea clutter. Thirdly, on the basis of observed sea clutter of S-band radar, the fractal dimension and the largest Lyapunov exponent are obtained, which proves its chaos and fractal characteristic. Finally, the computer simulation is carried out and the results prove the effective detection performance and noise tolerance.