For welding of TC4 titanium alloy of fuel cell,the single-mode fiber laser were used for the experiment.Three factor and three level orthogonal testing of laser power,welding speed and focal distances was carried.Appearance and shear strength were tested.The best process parameters was that laser power was 100 W,welding speed was 60 mm/s and focal distances was 3 mm.Shear strength of welds reached to the highest of 588 MPa and no breakdown caused on the lower layer material.Under conditions of the best process parameters,closed welding track was taked, and air tightness and corrosive of welds was tested. Corrosive testing was carried out in condition of acidic to test discoloration on the surface of welds.Testing result showed that gas tightness and corrosive of welds met the demand of fuel cell,and achieved actual production conditions.