The present invention relates to an ionic phosphorescent metal complex and its preparation method and use. The structure of the complex is shown in general formula (I), wherein, R 1 and R 2 The same or different, independently selected from: alkyl, aryl, heteroaryl; said alkyl, aryl, heteroaryl are optionally substituted by 1-5 of the following groups: halogen, alkyl, alkoxy , alkylthio, amino, alkylamino, dialkylamino, arylamino, diarylamino, haloalkyl, cyano, nitro, alkenyl, aryl, optionally substituted by 1-3 aryl groups The heteroaryl; R 3 Optionally halogen, alkyl, haloalkyl, alkoxy, alkylthio, amino, alkylamino, dialkylamino, cyano, nitro, alkenyl, etc.; M is optionally: Cu(I), Ag(I), Au(I). The present invention also relates to an organic light-emitting diode and its preparation method and application. The organic light-emitting diode prepared by using the phosphorescent metal complex described in the present invention as the light-emitting layer dopant has high-performance organic electroluminescence, and can be applied for lighting and flat panel displays.