In the present study, the magnetic properties of three-dimensional topological insulators, doped with magnetic atoms are investigated. The spin-orbit locking of surface electrons results in interesting magnetic behaviors, absent in conventional insulators without spin-orbit coupling. One of these behaviors is the strong dependence of ferromagnetic paramagnetic transition temperature on different system parameters. Here, using the mean-field formalism, we have studied the effects of hexagonal warping on the order parameter, critical temperature, and magnetic susceptibility of system.