The Polistes rothneyi grahmi Vecht is reported about its biological characters in building nest for the first time,including aspects of locating,constructing,ec ological adaptation,nest-building behavior,etc. The Polistes rothneyi is selec tive in the location of its nest, trees and eaves sheltered from the wind and su nlight are the common selections; taking the first four cabinets as basis and co re, the Polistes rothneyi places new cabinets round and round, every cabinet is at the junction of other two cabinets; the shape and construction of the nest of Polistes rothneyi are resulted in the long struggle of survival, adapting to th e natural environment and coordinating with their living activities such as buil ding nests, laying eggs, growing of larvals, pupating, etc.:1) The building of the nest is for the sake of reproduction, so the need in reproduction has great effect on it, that is, the conditions in laying eggs, growing of larvals and pu pating determine the number and size of cabinets;2) The round-shaped, cymbal-li ke structure and the location of eggs in nests reflect the adaptation of surviva l.