The male sex differentiation in crustaceans is mainly regulated by the insulin-like androgenic gland hormone (IAG) secreted by the androgenic gland (AG). In Macrobrachium rosenbergii, manipulation of the IAG can lead to a full-functional reversed female, which is used to produce all-male offspring. Therefore, the IAG-based sex regulation technique has its application potential. At present, IAG has been reported in many economic crustaceans. It is found that IAG expression is not limited to the AG, and its function is more extensive. With the application of RNA interference technology in aquatic animals, the study of gene function is more easily realized. Therefore, the signaling mechanism of IAG function and its upstream regulatory network have gradually become a hot topic. This paper reviews the recent research progresses in the regulation of gene expression, molecular characteristics and biological functions of IAG, as well as the signaling mechanisms of IAG function. Summary of these researches will provide a basis for further elucidation of the physiological function of IAG, as well as its mode of action.