Aluminium-lithium alloys have great application potential in aerospace component preparation. Selective laser melting (SLM) technology has unique advantages in the integral formation of complex and lightweight structures, but the mechanical properties of Al-Li alloys formed by SLM directly are poor, requiring heat treatment to maximize their mechanical properties. This study examined the impact of T6 treatment and double-stage aging on the microstructure and properties of a 2196 Al-Li alloy built via SLM. The results demonstrate that after 170 ℃/36 h (T6) aging treatment, the strength is greatly improved because of the precipitation of nano-T1 (Al2 CuLi), but the elongation decreases dramatically. After the 130 ℃/6 h+170 ℃/24 h aging treatment, the samples show both greater strength and elongation than those in the T6 state because of the smaller size and higher number density of the T1 phase. After the 170 ℃/36 h+115 ℃/4 h aging treatment, a large number of additional atomic clusters form in the alloy, and the strength increases again while the elongation is maintained at the same level.