Synchrotron radiation x-ray diffraction experiments on the pressure-induced ferromagnetic superconductor UGe2 has been performed using a diamond anvil cell (DAC)diffractometer to study the correlation between the crystal structure and ferromagnetism. The oscillation photos covering the three-dimensional reciprocal spaces were taken both below and above a critical I entperai uni T-x at pressures up to 1.1 GFa. Coupled charge density wave (CDW) tnul spin density wave (SDW) fluctuations were predicted as an origin of unusual properties of UGe2 by Watanabe and Miyake, but no additional superlttice Bragg peaks corresponding to the CDW reflections could be observed, resulting in an upper limit of its intensity of similar to 1 x 10(-4) to the fundamental Bragg peak intensity.