Radiation pressure of electromagnetic fields have been widely used in nanomanipulation and tunable optics, but the interplay between the gradient force and the scattering force results in limited working range. Here we show that the complete suppression of backscattering in photonic topological materials provides new ways of controlling optical forces: long range optical pulling forces exist in any line defect containing multiple edge states, while long range conservative potentials can be established with single-mode edge states. Broken time-reversal symmetry in such systems can be potentially realized with enhanced optomechanical coupling in waveguides, which creates coherent acoustic waves at GHz frequencies, particularly with the involvement of graphene photonic crystals.