Hydrogen embrittlement has strong microstructural sensitivity, which threatens the safe service of all kinds of high strength structural materials. BS960E high strength steel is welded by laser-arc composite welding process, and the joints are subjected to slow strain rate (10^-5 s^-1) tensile test under the condition of in-situ electrochemical hydrogen charging. The microstructure and fracture characteristics of the joints are analyzed, and the hydrogen embrittlement behavior of the joints is studied. Results show that the welding thermal cycle of rich martensite formed by fine grain area can make joint show some hydrogen embrittlement sensitivity, martensite higher hydrogen diffusion coefficient and lower hydrogen solubility and rapid diffusion of hydrogen on the grain boundary is the main cause of joint is sensitive to hydrogen embrittlement, by controlling the welding process parameters can inhibit the welding thermal cycle caused by the martensitic transformation, it can reduce the hydrogen embrittance sensitivity of BS960E high strength steel laser-arc composite welding joint.