The invention discloses a method for preparing surface-modified hydrophobic polyimide weaving cloth. The method comprises the following steps: (1) immersing weaving cloth in polyimide sol, taking out the weaving cloth from the polyimide sol at a uniform speed, and drying so as to obtain the polyimide weaving cloth; (2) soaking the polyimide weaving cloth in ethanol, washing with water, and drying so as to obtain the dried polyimide weaving cloth; (3) soaking the polyimide weaving cloth in an alkaline solution, taking out the weaving cloth after soaking, washing with water, then soaking in an acid solution, taking out after soaking, washing with water, and drying in a drying oven so as to obtain the dried polyimide weaving cloth; and (4) uniformly dripping a fluoroalkyl silane solution to the surface of the dried polyimide weaving cloth, carrying out a hydrolysis reaction in a sealed container, taking out after the reaction, drying in the drying oven, and evaporating to remove the unreacted fluoroalkyl silane, thereby obtaining the surface-modified hydrophobic polyimide weaving cloth. The method is simple and feasible, and the prepared surface-modified hydrophobic polyimide weaving cloth has excellent hydrophobic property.