Abstract: Arc additive manufacturing technology carried out the single-channel multi-layer reciprocating deposition experiment of pure nickel welding wire on Q235 steel substrate. The effects of deposition current, deposition speed, and interlayer temperature on surface forming quality were studied and analyzed. The results show that when the wire feed deposition speed ratio is constant, the current and surface roughness increase. When the current is constant and the deposition rate increases, the surface roughness decreases first and then increases. Only when the interlayer temperature increases does the surface roughness increase, the overheat time of the heat-affected zone metal during pure nickel additive increases the tendency of hot crack formation. Therefore, based on the finite element analysis, a prediction model of the relationship between interlayer temperature and cooling time is established and verified with the experimental results. For the feedback of sediment width, by designing a visual monitoring sensing system, the height detection and width detection are combined, and the image processing algorithm such as Laplacian operator edge detection is used for fitting to obtain the size data of deposited metal in real-time and provide feedback data for the subsequent closed-loop control process.