The structure of liquid mercury is determined by 0 -20 type powder diffractometer. A new simple method is proposed to analy the structure of non-atom liquid by using the intensity diffraction profiles. It is found that the space between two nearest neighbor Hg atoms is 3.00 A and the second near neighbor atoms is 3.38 A. The method of peak separation for X-ray diffraction profile is proved to be effective by applying to non-atom liquid system.