Abstract: In order to reduce the material and equipment cost and improve the wire shape freedom in the additive manufacturing of titanium alloy, TA2 metal strip was fused by fiber laser with different laser power after pre-welded on TC4 substrate, the forming and the microstructure of the sample was observed by the ultra depth of field optical microscope. The results show that under the test parameters, when the laser power is 2500 W, the surface of the sample is flat, and the microstructure is duplex microstructure composed of uniform and fine lamellar β transformation organization α' and intergranular β+ a small amount of primary equiaxed α phase. There are no pores and cracks observed in the additive layer.The good metallurgical bonding is achieved between the additive material and the substrate and the fusion line is obvious.Pores appear at the joint between the additive layer and the substrate when the laser power is too low(2000 W), and the sample has a bad forming situation.The microstructure in additive layer coarsens and the solidification segregates seriously when the laser power is too high(3000 W).