In this study, we selected Sebasticus marmoratus as an indicator species to evaluate the habitat suitability of rocky reef fishes in the Ma'an Archipelago. Indicator factors of S. marmoratus's habitat (i.e. water depth, salinity, chlorophyll a, turbidity, and substrate) were obtained in the spring and winter of 2009. Subsequently, a suitability curve was developed and the Habitat Suitability Index (HSI) of S. marmoratus at each sampling site was calculated. It is shown from the results that:1) The HSI of alongshore sites around the Lvhua, Huaniao, and Shengshan Islands are generally low, while those around the Gouqi, Sanheng, and Dongku Islands are relatively high, with the maximum (1.0) recorded at the sites around the Gouqi Island; 2) The most suitable water depths in spring are 6 and 8-12 m for the juvenile and adult S. marmoratus, respectively, while during winter, the latter depth is mostly inhabited by S. marmoratus; 3) For spring, the suitable salinity was 30 PSU for all size groups, whereas in winter, it ranges from 27 to 31 PSU for juveniles,and appear to be 27 and 31 PSU for adults; 4) The suitability decreases with increasing chlorophyll a and turbidity, noting the most suitable substrate type as rocky bottom; 5) Correlation analysis shows that the abundance of S. marmoratus is highest correlated with sediment type but negatively correlated with both chlorophyll a and turbidity. The results imply that high primary productivity and turbidity may significantly reduce the S. marmoratus population size. Substrate type is the most important factor for S. marmoratus distribution. In particular, the rocky reef habitat occupied by kelp was the best living environment for S. marmoratus. Finally, we verified the HSI model with data from our surveys and fishery production in spring and winter of 2010, which shows that S. marmoratus abundance increases with higher HSI values. Therefore, we are confident that the HSI model we constructed is applicable for assessing the habitat suitability of rocky fishes in rocky reef areas.