Temperature dependences of synchrotron radiation diffuse scattering on the model relaxor single crystal Sr0.6Ba0.4Nb2O6 (SBN-60) have been studied in the temperature interval from 90 to 290 K in the vicinities of lattice points (332), (412) and (002) in the [001], [010] and [1 0] directions. This diffuse scattering (DS) has been shown to be a strongly anisotropic with intensity IDS(T, q) proportional q–α where q is a reduce wavevector. The temperature dependences of the parameters α have been obtained, and it is established, that the microscopic modification of structure in the SBN-60 continues on cooling below the temperature of transition to the relaxor state.