The invention provides a static pressure floating rotary worktable of a heavy machine tool. The tool comprises a base and a workbench rotating disc, wherein the workbench rotating disc is positioned above the base, and a plurality of guide rail units which are uniformly distributed are arranged on the upper surface of the base; each guide rail unit comprises a guide rail surface and an oil cavityarranged in an area of the guide rail surface; the static pressure floating rotary workbench further comprises a constant-current static pressure hydraulic system, wherein the constant-current staticpressure hydraulic system comprises a pump station, an oil tank and an oil spraying mechanism communicating with the oil cavity and the pump station; and an oil return groove is formed in the inner side of the annular uniformly-distributed guide rail unit, an oil return hole is formed in the oil return groove, and the oil return hole communicates with the oil tank. When the machine tool is startedand the heavy part is machined, the working table turntable uniformly floats under the adjusted liquid pressure, so that the worktable turntable and the base guide rail are not in direct contact witheach other, the working table has good motion precision and larger loading resistance, and the service life of the base guide rail is prolonged.