The invention discloses a steel pipe pile welding and construction platform for a power transmission line foundation in the river and relates to a construction platform. In a traditional operation welding process, a basket is suspended by a floating crane in general, so that the safety risk is high and the operation difficulty is high. The steel pipe pile welding and construction platform comprises a platform body, a platform fence and a plurality of support rods, wherein the platform body surrounds the steel pipe pile; the platform fence is arranged at the upper part of the periphery of the platform body; the plurality of support rods are arranged at the lower part of the platform body and surround the steel pipe pile; the inner side of the platform body is fixedly connected with the side wall of the steel pipe pile through a plurality of connectors in a detachable manner; the bottom part of the outer side of the platform body is fixedly connected with the upper end of each support rod in a detachable manner; the lower end of each support rod is fixedly connected to the side wall of the steel pipe pile at the lower part of the platform body through the corresponding connector in a detachable manner; the platform body and the platform fence are combined and connected through detachable assemblies; and the platform body is detachably connected with the platform fence. According to the technical scheme, the construction platform is convenient for construction workers in construction, ensures the personal safety of the construction workers, is convenient to disassemble, transport and install, and can be repeatedly used.