This application discloses an optical backplane system, which includes a first upper-level optical interconnection module, a first lower-level optical interconnection module, and a second lower-level optical interconnection module. The first upper-level optical interconnection module includes M1 first interfaces and N1 second interfaces in connection relationships. The first lower-level optical interconnection module includes L1 third interfaces and K1 fourth interfaces in connection relationships. The second lower-level optical interconnection module includes L2 third interfaces and K2 fourth interfaces in connection relationships. The first upper-level optical interconnection module is connected to one of the L1 third interfaces of the first lower-level optical interconnection module by using one of the N1 second interfaces. The first upper-level optical interconnection module is connected to one of the L2 third interfaces of the second lower-level optical interconnection module by using another one of the N1 second interfaces.