Abstract: Laser welding between Kovar alloy and DM308 Mo glass using YLS-6000 fiber laser was performed. The effects of process parameters on joint strength and interface microstructure were studied as well as diffusion behavior of interface elements. The result shows that: (1) When the laser power is 700-800 W, the welding speed is 4.5 mm/s and the focal distance is 0 mm, the joint shear strength reaches the maximum value of 10.97 MPa; (2) The bonding quality of Kovar alloy/DM308 glass is generally good. A thin reaction layer was observed at the interface. The boundary between the welded seam and the substrates is clear. Microcracks exist in some positions of interface due to the presence of a lot of pores in the glass side; (3) Under high temperature conditions, the element diffusion is more uniform, the more Fe2SiO4is generated at the interface reaction, and the joint strength is the higher.