Summary: To resolve the combination of subdivision surfaces, a kind of Loop’s subdivision algorithm which satisfies the boundary conditions is presented [cf. C. Loop, Smooth spline surfaces based on triangles, Diss. Utah: University of Utah (1987)]. The combination of two Loop’s models can be achieved using this algorithm. The limit surfaces of the two Loop’s models with the same subdivision format are \(C^2\)-continuous on the boundary, but they are \(C^1\)-continuous at the singular point.