Abstract: With the development of techniques, terahertz devices have been gradually applied in space industry, where terahertz mixers serve as core components for transceivers and are being widely utilized across various satellite models. However, there is currently no application of satellite-borne terahertz mixer in China, indicating a noticeable gap compared to foreign counterparts, necessitating increased investment and development efforts. This paper introduces an assembly technology of satellite-borne 220 GHz mixer-characterized by stringent design requirements, complex structures, and high precision assembly demands. In this paper, according to the structural and electrical performance characteristics of the product, fine needle adhesion method, narrow-gap low-stress conductive adhesive mounting method and high-precision gold wire bonding technology are adopted to achieve high-precision soldering of micron-sized terahertz diodes (accuracy of ±10 μm), precision mounting of large-sized high-aspect-ratio quartz substrate (2.24 mm×0.73 mm×0.127 mm) and high-precision, high-conformity wire interconnections (span of ≤ 150 μm, arch height 50 μm ~100 μm). The electrical performance of the assembled product is basically consistent with the simulation results, effectively solving the assembly problem of terahertz mixers for aerospace applications.