The preparation method includes the following steps: dissolving aripiprazole in an acidic solution having an acidifier so as to obtain a medicament having acidic solution; then, performing a wet granulation on or preparing a suspension with the obtained medicament having acidic solution, an alkalizer, and an excipient so as to obtain the aripiprazole medicament formulation; the excipient comprising an antioxidant. The aripiprazole medicament formulation obtained through the preparation method has a significantly reduced amount of related substances, great solubility, great stability, high bioavailability, reduced individual differences, and enhanced wettability and content uniformity of insoluble medicaments.