Banyan optical networks play an important role in free-spatial photonic networks. The characteristics and structures of two-dimensional (2D) banyan network are analyzed. A new 2D banyan network architecture, which consists of polarizing beam-splitters, 4×4 micro blazed-grating arrays, half silvered mirrors, 4×4 spatial light modulators and mirrors, is proposed to accomplish optical signal switching, multicasting, broadcasting and matrix conversion through the 4×4 2D planes. The 4×4 micro blazed-grating arrays fulfill vertical connection and horizontal connection switching in 2D banyan networks, while the mirrors perform straight connections. The theoretical analysis shows that the architecture has the advantages of transparent switching, high speed, and high space-bandwidth product, therefore it can be implemented in free spatial optical interconnection widely.