The invention discloses a quick locking mechanism and an LED combined screen. The locking mechanism comprises a first connecting part and a second connecting part, wherein the first connecting part comprises a first mounting site, the second connecting part comprises a second mounting site, a locked mechanism which is not in complete contact is located by the seamless splicing and fixing of the first mounting site and the second mounting site, the axial tangent planes of the first mounting site and the second mounting site are trapezoid, the first connecting part further comprises an elastic fixing piece, and a slot is formed in the elastic fixing piece; the second connecting part further comprises a sleeve fixing seat fixedly connected with the second mounting site, a sliding sleeve with an elastic device is arranged in the sleeve fixing seat, a locking hinge pin with one end provided with a clamping site is fixed on a rotating handle, the locking hinge pin penetrates through the sliding sleeve and the sleeve fixing seat, and locking can be achieved by the buckling connection of axial holes of the second mounting site and the first mounting site with the slot in the elastic fixing piece.