The invention discloses a preparation method of low-yellowness antibacterial calcium carbonate functional composite powder for a ventilated membrane. The method comprises the following steps of: cleaning calcite raw ore, drying in the air and smashing; grading with a vibration sieve; mixing for preparing; coating; drying; and modifying. The composite powder has the beneficial effects: when added into the ventilated membrane, the composite powder plays a role in filling and increasing volume; the yellowness of the ventilated membrane is lowered by over 50 percent in comparison to a ventilated membrane into which an equal amount of ordinary calcium carbonate is added; the processing flowability, tensile strength and air permeability uniformity of a ventilated membrane product can be improved remarkably; and the ventilated membrane added with the calcium carbonate-based functional composite powder has antibacterial property.