The invention discloses a construction method for a representative volume element (RVE) model of an Ni3Al-based alloy. The method comprises the steps that (1) an alloy microstructure is observed through a scanning electron microscope; (2) the distribution law of microcosmic geometrical characteristic parameters of the alloy microstructure is subjected to analytical statistics; (3) a constraint condition of a strengthening phase in an RVE is set; (4) coordinates of a key point of the strengthening phase in the RVE are generated; and (5) the RVE is generated. The method has the advantages that the generated RVE contains sufficient microcosmic information, covers microcosmic uncertainty of a material and can effectively describe mechanical properties in the material; by adopting the generated RVE to carry out mechanical analysis, a mechanical response of the material under a load can be predicted more effectively, and therefore the method has certain scientific theory significance and engineering application value.