Laser melting deposited TC17 alloy and forged TC17 alloy are welded by fiber laser. The microstructure, phase constitution and mechanical properties of the weld joint are studied by optical microscopy, scanning electron microscopy, X-ray diffraction and microhardness tests. Results indicate that the fusion zone (FZ) mainly consists of fine dendrite which nucleated and epitaxially grows from the substrates. The heat input makes the β grain of forged TC17 grow more seriously than that of laser melting deposited TC17. The heat affected zone (HAZ) of laser melting deposited TC17 is much narrower than that of forged TC17. Laser melting deposited TC17 exhibits better thermal stability than forged TC17. The microhardness of FZ is higher than that of the base metal, and the microhardness of HAZ is lower than that of the base metal.