The invention provides a joined plate welding platform, and relates to the field of joined plate welding. The joined plate welding platform comprises a first frame, a welding mechanism and an edge milling mechanism, and further comprises a second frame arranged with the first frame side by side; the first frame and the second frame are provided with clamping structures for mounting and positioningsteel plates; a milling and welding channel is reserved between the first frame and the second frame; the welding mechanism and the edge milling mechanism are movably mounted on the side, corresponding to the milling and welding channel, of the first frame; the moving directions of the welding mechanism and the edge milling mechanism extend in the length direction of the milling and welding channel; the second frame and the first frame are assembled in a relative translation mode; and the second frame extends in a direction perpendicular to the horizontal direction of the milling and weldingchannel relative to the translation direction of the first frame. In the milling and welding process, the steel plates have no need to be transferred from an edge milling station to a welding station;and through the translation motion of the second frame, the joint distance adjustment after edge milling is realized, the step of secondary positioning and clamping of the steel plates is prevented,and the whole joined plate welding operation is more convenient.