The invention relates to an automobile turbocharger shell and a preparation method thereof. The preparation method comprises the following steps: mixing the raw materials, i.e. silicon, iron, copper, magnesium, zinc, chrome, nickel, tin, titanium, lead, manganese and aluminum according to a weight ratio, performing smelting and pressure casting, taking out a product from a pressure casting machine, cooling the product, performing edge cutting, manual cleaning, X-ray flaw detection, carrying, blasting, five-axis precision machining, cleaning and deburring, ECM electrode deburring and ultrasonic cleaning, and performing drying, inspection, packaging and delivery to obtain the automobile turbocharger shell. According to the product produced by the preparation method of the automobile turbocharger shell, the shortcoming that the original thin-wall turbocharger shell has extremely large air holes is overcome; and by the optimization for the design of the domestic advanced die pressure casting technology with one die and one cavity, the technical requirement that each air hole of the turbocharger shell is less than 0.2 mm can be met.