Habitat suitability assessment is an important prerequisite and basis for assessing biological resources and protecting biodiversity. Based on the survey data of macrobenthos and environmental factors in the summer, autumn, and winter of 2020 in the mangrove of Yanpu Bay, we have studied the habitat suitability of macrobenthos. In this study, Cerithidea largillierti, the dominant species of macrobenthos, was selected as the research object. A Generalized Additive Model was used to screen environmental factors, and the relative weight method was used to determine the weight of environmental factors. Then, the habitat suitability model was established by using the Weighted Average Model and Geometric Mean Model, respectively, and the optimal model was established based on cross check and Akaike Information Criterion (AIC). The results showed that the Habitat Suitability Index model based on Geometric Mean Model was the best fit model, and temperature, ammonia nitrogen, reactive phosphate, dissolved oxygen, electrical conductivity, nitrite, pH, and nitrate with the minimum AIC value were selected as explanatory variables. The temporal Habitat Suitability Index showed that autumn ＞ summer ＞ winter. The spatial Habitat Suitability Index showed that offshore section ＞ middle section ＞ nearshore section, northwest section ＞ southeast section. The results showed that there was obvious spatial and temporal heterogeneity in the habitat suitability of C. largillierti in the mangroves of Yanpu Bay. The findings may be used to raise awareness among researchers and policymakers. In addition, more comprehensive and scientific surveys will help to better understand the habitat suitability of macrobenthos in the future.