Laser welding was used to weld 22MnB5 high-strength steel in deep penetration welding and heat conduction welding. Aluminum foil was added on the surface to control the content of Al element in the welds, and the effects of Al content on the microstructure and mechanical properties of 22MnB5 steel welded joints was studied. Results showed that, in both deep penetration and heat conduction welding, an increase in Al content in the weld led to an increase in surface defects such as collapse, undercut, porosity and Al-rich weld slag. The microstructure of the welded joint mainly consisted of lath martensite and α-ferrite, with Al-rich intermetallic compounds (IMCs) disperse near the upper and lower weld toes close to the coating. The Al element homogenization in the weld was better in heat conduction welding compared to deep penetration welding. The microhardness of weld showed higher hardness in weld center and lower hardness at weld edge. With an increase in Al content, the density of α-ferrite increased, then led to a reduction in microhardness. The tensile strength of both deep penetration welded joint were higher than the heat conduction welded joint, especially with Al coating on the upper surface. When the weld Al content is 0.47%, the tensile strength of welded joint is 1 477 MPa.