The invention relates to an optical receiving assembly for hundred trillion-grade 850nm optical communication and a preparation method thereof, and provides an optical receiving assembly for hundred trillion-grade 850nm optical communication, which is compatible with a commercial CMOS process and can replace the hybrid integration in the traditional 850nm optical transceiver and meet the transmission requirement, and a preparation method thereof. The optical receiving assembly is provided with a 850nm optoelectronic single integrated receiving chip, a pipe seat, a pipe cap, a pipe pin and an adapter, wherein the chip is provided with a prepositive amplifying circuit and an optoelectronic detector, and the prepositive amplifying circuit is provided with two mutual resistance type amplifying circuits, a three-grade differential amplifier, an output buffer circuit and a direct current negative feedback circuit. The optoelectronic detector is provided with a low doped P-shaped silicon substrate, a P pit, an N-shaped heavy doping silicon layer, a field oxide layer, an aluminum layer, three SiO2 insulating medium layers and a Si3N4 surface passivating layer from bottom to top in the longitudinal direction. The chip is attached to the pipe seat by a CMOS process; a welding disk of the chip is bonded with the pipe pin by a gold thread; and the pipe cap is covered to be encapsulated with the adapter according to the same shaft.