Porous magnesium (Mg) scaffolds are beneficial to biological implantation, but because of the high activity of Mg, the degradation rate after implantation is too fast, which is not conducive to the formation of new bone. In order to effectively control the degradation of Mg scaffolds, three different surface coatings, magnesium oxide (MgO), calcium hydrogen phosphate (DCPD) and stearic acid (SA) on the porous Mg scaffolds was prepared and their effects on the scaffolds were investigated. The surface composition of the uncoated scaffold and the coatings was confirmed to be pure Mg, MgO, DCPD and SA by energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and Fourier transforms infrared spectra (FTIR). The results show that SA coating is smoother and more compact in surface morphology. In vitro degradation in simulated body fluid (SBF) indicates that surface coatings can effectively slow down the scaffold degradation, while DCPD coating and SA coating are better than MgO coating in resisting the degradation. The degradation rate of the scaffolds with DCPD and SA coating soaked in SBF is 70% at the 15th week, which provides a certain period of time for the growth of new bone.