We have carried out the hohlraum experiments about radiation temperature scaling on the Shenguang-Ⅱ(SG-Ⅱ) laser facility with eight laser beams of 0.35μm, pulse duration of about 1.0ns and total energy of 2000J.The reradiated x-ray flux through the laser entrance hole was measured using a soft x-ray spectrometer. The measured peak radiation temperature was 170eV for the standard hohlraum and 150eV for the 1.5-scaled one.We have derived the radiation temperature scaling law, in which the laser hohlraum coupling efficiency is included.With an appropriate coupling efficiency, the coincidences between experimental and scaling hohlraum radiation temperatures are rather good.