Disclosed is a Re alloy coating for diffusion barrier, such as a high-temperature equipment member, which comprises an atomic composition of 30% to less than 90% Re; and an atomic composition of 5% to less than 60% X (wherein X is at least one selected from the group consisting of Cr, Mo and W), with the remainder except for inevitable impurities being at least one selected from the group consisting of Ni, Fe and Co. Even if the alloy coating for diffusion barrier includes a diffusion layer containing at least one of the group consisting of Al, Si and Cr, a desired alloy composition of the alloy coating for diffusion barrier can be assured by a surface coating process and diffused components from the substrate while substantially preventing the diffusion of the elements of the diffusion layer during a homogenizing heat treatment. The alloy coating for diffusion barrier may include a Re-containing-alloy stress relief layer inserted between the film and the substrate. The Re alloy coating can suppress the deterioration of the substrate and the coating layer due to the reaction therebetween to provide an extended life span of the equipment member.