Stingless bee (Trigona sp.) need pollen as food source for growth of colony. The number of colony depends on available supply of melliferous species. We studied morphology of pollen from hive-returning stingless bee pollen load and analyzed the plant community in the deciduous forest of Queen Sirikit Botanic Garden, Chiang Mai provinec, Thailand. The Trigona collina Smith. visited 18 from 70 flowering species around the year. These pollen florae were Litchi (Litchi chinensis Sonn.), Tin tukkae (Tridax procumbens L.), Plao yai (Croton roxburghii N.P. Balakr.), Rok faa (Terminalia alata Heyne ex Roth), Phang rae yai (Trema orientalis (L.) Blume), Chaa paen (Callicarpa arborea Roxb.), Kamlung suea khrong (Betula alnoides Buch.-Ham. ex G. Don), Phrik (Capsicum frutescens L.), Arang (Peltophorum dasyrachis (Miq.) Kurz), Thalo (Schima wallichii (DC.) Korth.), Maiyarap ton (Mimosa pigra L.), Po lom pom (Thespesia lampas (Cav.) Dalz. & Gibs.), Khaa hot (Engelhardtia serrata Blume), Ya yung (Capillipedium parviflorum (R.Br.) Stapf), Sieo dok khaao (Bauhinia variegata L.), Kaafaak (Scurrula sp.), Graminae and Verbenaceae. The flora species visited by the stingless bees was not related with the importance value index (IVI) and density of the given species. The result suggests that there is the preference behavior of pollen collection for the stingless bee. This information is useful for monitoring and conservation management of this bee species.