Using the self-developed electromagnetic stirring device to assist titanium alloy laser deposition repair, numerical simulation was carried on by finite element software ANSYS, the interaction relations of titanium alloy in laser molten pool was studied combined with experiment. The results show that the magnetic flux intensity on liquid surface is proportional to the excitation current and inversely proportional to the current frequency in laser molten pool with the influence of rotary magnetic field; the laser molten pool is impacted by the radial force and tangential force, but the former is lesser and it can be neglected, the maximum of electromagnetic force density on liquid cross-section is proportional to the excitation current. Surface on both sides of laser deposition repair parts bulge under the effect of rotating magnetic field and length to diameter ratio of lamellar α/β in laser repaired zones reduced.