A bearing estimation method of navigation interfering source based on broadband constant beamwidth beams is proposed in this paper. In the case of receiving broadband barrage jamming signals by anti-jamming antenna array, the estimated bearing value can be obtained by constant beamwidth beam-forming, then a group of linear equations with three elements for the outputs of constant beamwidth beams is solved. The new method which is introduced in this paper has good performance for the bearing estimation error than that of the broadband beam amplitude comparison method based on the outputs of conventional broadband beams. The simulation results verify the effectiveness and practicability of the method in this paper.