The invention relates to the field of aluminum-sulfur batteries, and discloses a positive electrode material for an aluminum-sulfur battery and a preparation method thereof. The positive electrode material comprises a positive electrode active material, a conductive agent and a binder, wherein the positive electrode active material includes an aluminum element, a sulfur element and an optional transition metal element M, wherein the chemical formula of M is AlxM2-xS3, and x is large than x and smaller than or equal to 2. According to the aluminum-sulfur battery prepared from the positive electrode material, normal charging and discharging of the aluminum-sulfur battery can be achieved, a disembedding reaction is performed in the charging and discharging process, a discharging product and an electrolyte are not soluble mutually, and the prepared aluminum-sulfur battery has the high specific discharge capacity and the better circulatory stable performance. Meanwhile, the positive electrode material solves the problem that a negative electrode of an aluminum-sulfur needs to contain aluminum.