In this paper, we use the inverse design method to design an optical interconnection system composed of wavelength demultiplexer and the same direction waveguide crossing on silicon-on-insulator (SOI) platform. A 2.4 μm × 3.6 μm wavelength demultiplexer with an input wavelength of 1.3-1.6 μm is designed. When the target wavelength of the device is 1.4 μm, the insertion loss of the output port is - 0.93 dB, and there is - 18.4 dB crosstalk, in TE0 mode. The insertion loss of the target wavelength of 1.6 μm in TE0 mode is - 0.88 dB, and the crosstalk is - 19.1 dB. Then, we designed a same direction waveguide crossing, the footprint is only 2.4 μm × 3.6 μm, the insertion loss of the wavelength 1.4 μm and 1.6 μm in TE0 mode is - 0.99 dB and - 1 dB, and the crosstalk is - 12.14 dB and - 14.34 dB, respectively. Finally, an optical interconnect structure composed of two devices is used, which can become the most basic component of the optical interconnect network. In TE0 mode, the insertion loss of the output wavelength of 1.4 μm at the output port is - 1.3 dB, and the crosstalk is - 29.36 dB. The insertion loss of the output wavelength of 1.6 μm is - 1.39 dB, and the crosstalk is - 38.99 dB.