The invention relates to an aluminum silicon alloy refining agent and the manufacturing method, which belongs to the aluminum silicon alloy refining agent research and development field. The aluminum silicon alloy refining agent is configured of potassium chloride, sodium chloride, zinc chloride, sodium fluoaluminate, sodium fluosilicate, sodium nitrate, graphite powder, charcoal powder, hexachoroethane, sodium fluoborate and potassium fluotitanate. The materials are mixed, smashed and pressed into blocks. The using method of the manufactured refining agent: when the temperature of the melted aluminum alloy fluid reaches 720 to 760 DEG C, the refining agent blocks are put into a melting pot to perform the reaction. The reaction time is 10 to 25 minutes. The floating slag is removed, and then the product is cast. The method of the product is simple, the implementation is easy, and when the refining agent manufactured in the method is used for the casting of aluminum silicon alloy, air holes can not be formed on the cast product surface, the content of oxide inclusions in the cast product is obviously reduced, and the cast product quality is greatly improved. The air holes can be reduced by one to two grades. The level of the oxide inclusions is about the second grade. The aluminum silicon alloy refining agent solves the problem that the prior refining agent and the processing method are not ideal.