Aiming at the problem of implementing optical buffers in the present high performance computer optical interconnection, a bufferless optical interconnection, named BOIN, is put forward. Based on modeling and analyzing the network topology, the relationship between the network throughput and the offered loads as well as network sizes is studied. Then the condition of maximum throughput of the network in a fixed offered loads and total number of nodes is presented. Finally, the simulation results show that the correctness is confirmed.