The invention relates to the technical field of micro-electronic and optoelectronic devices, and discloses a manufacturing method of a QSFP (Quad Small Form-factor Pluggable) module subelement which comprises the following steps: step 1, prefixing a transmitting terminal reflecting mirror (202) and a receiving terminal reflecting mirror (203) on a daughter board (201); step 2, etching a first concave pit (206) and a second concave pit (207) on a mother board; step 3, coating a fixed layer (205) on the bottom surface of the inner walls of the first concave pit (206) and the second concave pit (207); and step 4, protecting the places not requiring etching through a mask plate, and etching integrally again to form an optical waveguide layer (304). The QSFP module subelement manufactured by the method can be produced on a large scale, and the processing technology and the existing micro-electronic technology are compatible.