Quantitative analysis for the spatial distribution of fish is one of the important methods in fishery or fish ecology research. In this paper, the indexes Geary c and Moran I for the density distribution of demersal fish were calculated, and the semivariograms were drawn. The values of Geary c and Moran I were 0.38 and 0.52, respectively, and the C0/C0 + C was 59.9%, which meant that the distribution had a medium spatial autocorrelation with anisotropy, and the heterogeneity caused by random was a little higher than that caused by spatial autocorrelative process. The annual fluctuation of density was caused by the spatial autocorrelation and the random, because the density was significantly positively correlated with the values of C, C0 and C + C0, respectively.