The present invention provides a bi-direction optical assembly with two optical transmitting channels by a small-sized package and relatively low cost. In the bi-directional optical assembly, the first transmitting optical subassembly (TOSA) and the receiving optical subassembly (ROSA) are optically coupled with the optical fiber via the inner housing. While the second transmitting optical subassembly is optically coupled with the optical fiber via the outer housing slidable to the inner housing.