The invention discloses a method for preparing tetrabasic lead sulphate by extending a PbO production technology with energy conservation and without additional heating. The method fully and effectively utilizes PbO, as a product of the PbO production technology, and heat generated after product calcining. By implementing the method provided by the invention, the characteristics of low energy consumption, high production efficiency and production cost conservation can be realized, produced products are uniform in morphology similarly, generated waste liquid can be recycled, and the method is a novel preparation method which cannot bright environment pollution.