Magnesium (Mg) alloys are considered to be a new generation of revolutionary medical metals. Laser-beam powder bed fusion (PBF-LB) is suitable for fabricating metal implant with personalized and complicated structure. However, the as-built part usually exhibits undesirable microstructure and unsatisfied performance. In this work, WE43 parts were firstly fabricated by PBF-LB and then subjected to heat treatment. Although high densification rate of 99.91% was achieved using suitable processes, the as-built parts exhibited anisotropic and layered microstructure with heterogeneously precipitated Nd-rich intermetallic. After heat treatment, fine and nano-scaled Mg24Y5 particles were precipitated. Meanwhile, the α-Mg grains undergone recrystallization and turned coarsened slightly, which effectively weakened the texture intensity and reduced the anisotropy. As a consequence, the YS and UTS were significantly improved to 250.2 ± 3.5 MPa and 312 ± 3.7 MPa, respectively, while the elongation still maintained at high level of 15.2%. Furthermore, the homogenized microstructure reduced the tendency of localized corrosion, and promoted the development of uniform passivation film. Thus, the degradation rate of WE43 parts was reduced by an order of magnitude. Besides, in-vitro cell experiments proved its favorable biocompatibility.