The invention provides a large-scale IoV security data acquisition method. The method includes an initial step that each vehicle node acquires the legal certificate of an electronic commerce certification and authentication mechanism, all of the vehicle nodes are registered in a big data center, the information exchange between the vehicle nodes and the big data center can be completed by the forwarding of the intersection nodes and the registration of the intersection nodes in the big data center is completed during the forwarding; a primary single sign-on step that the vehicle nodes and the intersection nodes are connected to the big data center according to different protocols; a secondary sign-on step that when the vehicle nodes are far away from the intersection nodes connected in the primary sign-on step, the vehicle nodes establish connection with nearby new intersection nodes; and a safe data acquisition step that the vehicle nodes and the big data center realize the acquisition and the transmission of business data and secret data via the intersection nodes. The safe method adopted in each step is an independent system; and meanwhile, the continuity of the steps is guaranteed, and the security of data acquisition is guaranteed as a whole.