Synthetic organoselenium compounds can be used as antioxidants, enzyme inhibitors, neuroprotective agents, antitumor agents, anti-infectious agents, and immunomodulators. Diphenyl diselenide (DPDS) is a synthetic organoselenium compound with simple and stable structure, and possesses lower toxicity than inorganic selenium and most organoselenium compounds. Moreover, DPDS has strong antioxidant properties due to its strong glutathione peroxidase-mimetic activity, involvement in thioredoxin reductase catalytic reactions, and activation of the nuclear factor E2 associated factor 2 (Nrf2)/Kelch like epichlorohydrin associated protein-1 (Keap1) signaling pathway. DPDS has been shown to possess a variety of pharmacological activities including anti-inflammatory, anti-diabetic, antifungal, neuroprotective, antitumor, hepatoprotective, renoprotective, and cardiovascular protective effects in a variety of animal and cellular models. This paper reviews the research progress on the physicochemical properties, main pharmacological effects and mechanisms of DPDS by compiling relevant research results, so as to provide reference for future research and reasonable development and application of DPDS.