Hurst's exponent of radial distribution functions (RDFs) within the short-range scope of In, Sn and In-40 wt%Sn melts are determined by the rescaled range analysis method. Hurst's exponents 𝐻 are between 0.94 and 0.97, which display long-range dependence. Within short-range scope, the number of particles from a reference particle belongs to fractional Brownian motion. After RDF serials are randomly scrambled, Hurst's exponents all dramatically dropped, which proves long-range dependence. 𝐻 irregularly varies as the temperature rises, but the change tendency is not consistent with the correlation radius 𝑟𝑐.