The efficient algorithm determining functions of cylindrical atoms distribution in a melt surface through experimental diffraction data has been proposed. The performed calculations for liquid copper enable to obtain characteristics of structure of the copper surface layer near order, namely, the shortest interatomic distance and coordination number, being equal to 0.243 nm and 9.2, respectively. The above model makes it possible to represent structural dependences in a compact form, convenient for the creation of data banks on diffraction studies.