Abstract: The voltage and the current are the two main parameters in high velocity arc spray (HVAS) system.The fluctuation of current is larger than that of voltage in arc spray process.So the fluctuation of current is of importance to the quality of coatings and the stability of arc spray process. In this paper,the influences of the current fluctuation to the porosity,hardness and abrasiveness of coatings are studied under the condition of the other parameters keeping constant.The fluctuation of current can induce the reduction in hardness and abrasiveness of coating,and the increase in porosity of coatings.So the properties of coating will be worse.The reason is that the larger fluctuation of current causes the larger nonuniformity in the size,temperature and distribution of spraying particles.