Abstract: Objective Resistance spot welding is the major welding technology of plate connection during vehicle body-in-white production. However, during the resistance spot welding process, the spatter of welding slag has a significant impact on the welding quality of Body-in-white, and can also cause equipment failures and other problems, thereby increasing repair costs and reducing production efficiency. Therefore, this article conducts research on the analysis and control methods of the causes of spatter in resistance spot welding of body-in-white. Methods A set of operational procedures for analyzing and controlling the causes of spatter has been proposed, which analyzes the welding process and welding morphology from multiple dimensions, and then exactly implements targeted measures. The operational procedures for analyzing causes and controlling methods of spatter have been verified in actual production. Results During the verification process, optimization was carried out on the workstations with high spatter rates in the welding based on the analysis results, resulting in a reduction in the overall spatter rate from 14% to 6%, with spatter rate being over 50% lower than before optimization, effectively reducing the workload of the pre polishing workstations and the failure rate caused by spatter. Conclusion This work ensures the body-in-white welding quality and improves the produce efficiency. It provides the clear work guideline and experience insight for the follow-up spatter control. The welding spatter rate is one of the main control indicators of the welding workshop, and it should be continuously monitored, adjusted and maintained in the production process, and an effective standard process should be formulated to effectively control the spatter and reduce the impact of the spatter on the quality of the body-in-white.