We have proposed multi-level multi-accessible transmission using optical sheet bus technology which propagate diffusion controlled light in the planer optical waveguide. The optical signals which have a different intensity from two signal ports are added in the sheet and the multiplex transmission of 2×250Mbps is confirmed. The following relations are theoretically showed, multiplex level and received optical power uniformity ; multiplex level and crosstalk caused by reflection light from the opposite side under simultaneous bi-directional transmission ; crosstalk and Bit Error Rate. Result of bi-directional transmission at multiplex level of two corresponded to the calculation. Based on required transmission quality, multi-level multi-accessible bi-directional trnsmission system could be designed.