The invention discloses a manufacturing method for brass extracted from a waste automobile water tank. The brass extracted from the waste automobile water tank is equivalent to newly-prepared originalbrass in weight and chemical component. The manufacturing method mainly comprises the steps that after the surface is cleaned, reduction is conducted through microbial activities, and purification isconducted; and then vacuum electroslag remelting is conducted, and finally recycling is conducted. The recycling rate of the brass extracted from the waste automobile water tank is extremely high, and the recycled brass is good in quality, convenient to recycle, low in cost and wide in application range.