A novel thermal spray material of MoB/CoCr with high durability in molten Al and/or Zn alloys has been developed to utilize for die casting parts and for galvanizing bath parts. The durability of the MoB/CoCr prepared by high velocity oxy-fuel (HVOF) spraying was investigated using a molten metal immersing tester, where specimens were repeatedly immersed in a molten Al or Al/Zn alloys. The immersing test revealed that the MoB/CoCr coating has much higher durability in both Al and Al/Zn alloys than the conventional spray coatings, such as WC/Co, WC/Co/Cr and ceramics. As for MoB/CoCr coating, no reduction in coating thickness were observed after 600 hours of the immersion test. As for Al/Zn alloy, diffusion of alloys of mainly Zn is observed near the surface. However, diffusion rate of Zn into MoB/CoCr coating is much lower than that of conventional spray coatings. Therefore, the MoB/CoCr coating is excellent in increasing the lifetime of mechanical parts, which come into contact with molten Al or Al/Zn alloys.