An ionic phosphorescent metal complex complex has a formula of [PtM3{(PR″2CH2)3P}(C≡CR)(C≡CR′)(μ—Cl)]2+ An−2/n. M is selected from Au(I) and Ag(I). R, R′ and R″ are identical or different, and are independently selected from alkyl, alkenyl, alkynyl, aryl, and heteroaryl. Each of the alkyl, alkenyl, alkynyl, aryl, and heteroaryl may be substituted with one or more substituents selected from alkyl, alkenyl, alkynyl, alkoxy, amino, halogen, halogenated alkyl, aryl, and heteroaryl. The substituent is optionally further substituted with one or more of the following groups: alkyl, alkenyl, alkynyl, alkoxy, amino, halogen, halogenated alkyl, aryl, and heteroaryl. An− is a monovalent or divalent anion, n is 1 or 2, μ—represents bridging linkage. The organic light-emitting diode prepared by using the complex as the light-emitting layer dopant has an external quantum efficiency of 10% or more, and can be applied to the fields of flat panel display and daily lighting.