The elastic problem of anisotropic functionally graded rotating disks with non-uniform thicknesses was studied. The material properties and thicknesses of the disk change with an arbitrary gradient along the radial direction, and the disk displacement is constrained at the central axis of rotation and the edge is free. According to the equilibrium differential equations for the anisotropic rotating disk, the Fredholm integral equation of radial stresses was obtained, and then numerically solved to calculate the displacement and stress fields. For any specific situation of gradient change, it is only needed to substitute the corresponding gradient parameters into the equation for solution. In the numerical examples, firstly, the parameters such as the thickness and the elastic modulus were assumed to be of special power functions. The numerical solutions obtained from the Fredholm integral equation were compared with the corresponding exact solutions and the FEM solutions by the ANSYS software for the common Voigt model, to validate the method. Then, the effects of the thickness change, the gradient parameters and different degrees of anisotropy on the stress and displacement fields, were numerically analyzed with the common Voigt model. The proposed elastic analysis method for disk structures with arbitrary gradient changes along the radial direction, is promising in the application of structural optimization. The analysis results can guide the engineers to design safer and more economical functionally graded structures.