The work aims to preliminarily explore the ballistic behavior of armor steel weld zone and propose measures to improve the protection capacity. By analyzing the structure and properties of the armor steel welding structure and testing the ballistic behavior, the effects of welding on the ballistic behavior of armored vehicles were obtained. And countermeasures for improving the ballistic behavior of armored vehicles were discussed. The width of armor steel joint weld zone reached 46 mm. The hardness of weld center was lower than 312HV, which was 40% lower than that of base metal. The test results of ballistic behavior showed that the ballistic behavior of the weld zone was significantly attenuated compared with that of the base metal zone. To improve the overall ballistic behavior of armored vehicles, the welding process control, structural optimization and installation of protective components were discussed and the corresponding protective countermeasures were proposed for the weak points in the weld zone. The weld zone of armor steel is the weak point of ballistic protection. A series of protective measures should be taken to reduce the probability of being shot in the front of the weld zone and improve the ballistic behavior of armored vehicles during service.