The NiCoCrAlY+WC12Co coating with high density was prepared on the surface of the magnesium alloy by cold spraying. Effects of the WC12Co content on the wear behavior of coating were studied. The results showed that, under the dry friction condition, the weightlessness of wear of the coating with 20%WC12Co was smallest. The weightlessness of wear of the coating with 10%WC12Co was worse than that with 20%WC12Co. However, the weightlessness of wear of the coating without any WC12Co was worst among the three coatings. After the frictional experiment for 20 minutes, the weightlessness of wear of coating without any WC12Co was 10mg. Compared with that of coatings with 10%WC12Co and 20%WC12Co, the weightlessness of wear was lower than 35% and 54%, respectively. Obviously, the coating with 20%WC12Co had the capacity of the weightlessness of wear resistance. Consequently, the more the coating with WC12Co was, the higher the capacity of the weightlessness of wear resistance was.