1. An SOA-based integration method for 3D design system, characterized in that, the SOA-based integration method for 3D design system comprises the following steps: 1) constructing an SOA integration development system platform comprising four structural layers connected and communicated with one another, namely, from top to bottom, an application layer, a business layer, a service layer, and a resource layer; 2) setting at least one global model data server at the resource layer, and setting a design information integration platform at the business layer; 3) setting multiple pieces of third-party 3D model design system software at the resource layer, encapsulating them into WEB service through API program thereof, and setting the WEB service at the service layer; 4) setting database systems of the multiple pieces of third-party 3D model design system software at the resource layer, connecting the database systems to the global model data server through a data bus for mutual communication; 5) setting an integration web portal at the application layer, wherein the portal is integrated with sign-in links of the multiple pieces of third-party 3D model design system software.