Magnesium light weight alloys are currently being studied as implants due to their biodegradability. However, its applications are limited by high rate hydrogen evolution during corrosion. Coating on this substrate is one of the ways to reduce the rate of corrosion and increase the life of this type of implant. Hence, hydroxyapatite (HA) was coated on the substrates by using high velocity oxy- fuel (HVOF) spraying. The main purpose of such coatings is increasing bioactivity as well as corrosion resistance of the Mg alloy. Crystal structure was characterized by X-ray diffraction (XRD). Crystallinity of the coating was about 70% in which HA is dominant phase. The amounts of hydrogen gas released during magnesium corrosion tests in simulated body fluid (SBF) were measured to evaluate the corrosion resistance of the coated samples. This coating could decrease hydrogen evolution from 100 per cm2.mL to about 15 per cm2.mL after 29h of immersion time.