The 14 mm thick EH36 high strength steels are welded by the fiber-laser-MAG hybrid welding process. The effects of laser power, welding speed and welding current on the weld formation are investigated and the microstructures and perfomances of welded joint under the optimal process parameters are analyzed. The results show that the weld penetration increases and the weld width is basically unchanged with the increase of laser power. With the increase of welding speed, the weld width decreases and with the increase of welding current, the weld width is basically unchanged. Under the optimal welding process parameters, the weld formation is good and there are no welding defects. The microstructures of the heated affected zone and weld zone are mainly composed of lath martensite. The hardness of weld metal is greater than that of the base metal. The fracture position of the tensile specimen is within the base metal. There are no cracks on the tensile surface after the transverse bending test. The fracture morphology of weld impact specimen is quasi cleavage fracture.