Abstract: Marine shrimps, major fish preys, are important for marine ecological system. Generalized additive model (GAM) was used to analyze the relationship between crustaceans and environment factors, and to predict the distribution of dominance crustaceans in Ma′an Archipelago. Based on the model, the significant influence factors of Parapenaeopisis tenella were time and habitat type, and the significant influence factors of Squilla orarotia were habitat type, longitude, temperature and salinity. Time was the only significant influence factor of Palaemon gravieri. The distribution forecast map shows that the P.tenella biomass was higher in northeast of the survey area, and lower in the center area. Biomass of S.orarotia was higher in southeast area in March and in west area in October. The lower value of P.gravieri was in the center area, and the higher value was in surrounding area.