Abstract: The microhabitats of two grous of parasites, i.e. monogeneans and copepods, on gills of the bullhead catfish Pelteobagrus fulvidroco (Richarsson) were studied in this paper. The gill arches were numbered 1 to 4 from outside to inside, and cach arch was divided into there regions, i.e. ventral,middle and dorsal. Each gill filament cas divided into there segments: distal, middle and proximal.The difference in abundance between the right gill arch and the left was compared using Wilcoxon matched pairs test and no significant difference was found for monogeneans and copepods, respectively. The abundance on 4 different gill arches, 3 different gill regions and 3 different gill filament segments was analyzed by using a one way ANOVA. The number of the two groups of parasites on the fourth gill arch were both significantly lower than on the other there. The abundance on the middle region of the gill arch was significant higher than on the ventral and the dorsal for the two proups of parasites. The abundance of monogeneans on the proximal segment of the gill filment was significantly lower than on the distal and the middle. However, the abundance of copepods on the distal was significantly higher than on the middle and the proximal. The analysis of the distribution of the two groups parasites in different regions showed than the abundance of the two groups of parasites on the middle was the highest in the three regions, suggesting that there was no apparent competition in this habitat. Furthermore, the possible causes of the difference of abundance in different regions were discussed.