The invention provides a chip preprocessing method of selective epitaxial growth germanium silicon. The method at least comprises the following steps that (1) chip pre-washing is carried out; (2) a chip after pre-washing is arranged into a reaction cavity, hydrogen goes in, the chip is heated to a preset temperature, the hydrogen reacts with an autoxidation layer on the surface of the chip, and accordingly the autoxidation layer is removed; (3) then, hydrogen chloride gas is sprayed to the surface of the chip, and hydrogen chloride reacts with metal impurities on the surface of the chip, so that the metal impurities are dissolved; (4) the reaction cavity is vacuumized, so that surplus hydrogen, hydrogen chloride and impurities in the first two steps after reaction are removed; and (5) chip temperature is adjusted germanium silicon epitaxial growth temperature, and hydrogen carrier gas and hydrogen chloride selective gas go into the reaction cavity. According to the chip processing method, a hydrogen chloride gas way in existing equipment is used, hydrogen chloride processing happens in the reaction cavity, processing time is short, the technology is simple, the cleanliness of the chip can be greatly improved, and the quality of a following germanium silicon epitaxial layer can be guaranteed.