The invention discloses a reconfigurable automatic flexible welding production platform and an operation method thereof. The reconfigurable automatic flexible welding production platform comprises a production line main body, an accompanying platform, an accompanying fixture, a lifting mechanism, welding robots, a welding robot control center, a fixture transfer trolley, a fixture base and a production platform control center, wherein the accompanying platform can move on a line body; the accompanying clamp is positioned on the accompanying platform; the lifting mechanism is positioned on two sections of the line body; the welding robots are positioned at the two sides of a line body welding station; the welding robot control center controls movement of the welding robots and welding action of a fixed welding gun; the transfer trolley is responsible for replacing a fixture; the fixture base stores fixtures for producing different kinds of assemblies; the production platform control center controls movement of the whole production platform, wherein the movement comprises operation of a welding production line main body and operation of the lifting mechanism, so that high-flexibility requirements of automatic welding production for various small assembly components are reached, and production capacity is re-designed for realizing coordination of production tasks and production capacity.