The invention relates to the technical field of optical communication, in particular to an optical module capable of adopting liquid immersion refrigeration and a manufacturing method thereof, wherein the optical module includes a PCB board, an optoelectronic device, an optical lens and an optical connector; the optoelectronic device is installed on the PCB board , the optical lens is fixed above the optoelectronic device; one end of the optical connector is connected to the optical lens, and the other end is extended by an optical cable with a pigtail; the outside of the optical module is encapsulated by low-pressure injection molding materials, and the low-pressure injection molding materials meet: injection pressure 1.5 ~40bar, injection molding temperature lower than 110℃, adhesion with PCB board greater than 3000mpa.s, impedance performance matching with high-speed signal line of optical module. The optical module of the present invention is fully plastic-sealed with low-pressure injection molding materials, has low cost, high integration, and simple assembly, and can be used for a long time in a liquid immersion environment, effectively preventing the cooling liquid from polluting the optical path and interfering with the optical path.