Given the high sensitivity of hydrogen porosity in the welding process of AlSi10Mg aluminum alloy formed by selective laser melting, a study was conducted to compare the effect of dehydrogenation treatment on the pore defects of alloy laser welded joints using solid solution dehydrogenation and vacuum solid solution dehydrogenation methods, under different states. The study analyzed pore distribution, microstructure evolution, and mechanical behavior of laser welded seam. The findings reveal that the solution treatment can effectively reduce the porosity of AlSi10Mg aluminum alloy laser welded seam formed by selective laser melting. Vacuum solution treatment has the best effect, reducing porosity from 2.64% of the deposited state laser welding seam to 0.14% of the vacuum solid solution state weld. The study explains the reasons for the appearance of pores, analyzes the evolution of the joint structure, and examines the change of the phase morphology and composition of the substrate. It is revealed that vacuum heat treatment is an effective method for pore formation, solving the problem of hydrogen gas in the weld due to the high content of hydrogen pre-existing in the substrate. After solid solution, the hardness of the base metal decreased significantly, and the average hardness of the welds of each test plate was 80HV, which was relatively consistent. The tensile strength of the welded joint of the solid solution test plate was 143MPa, which was lower than that of the deposited joint, but the elongation increased to 24%, characteristic of ductile fracture.