The invention discloses a method for rapidly determining the content of zinc in an alkaline zinc-nickel alloy plating solution, which adopts polyethylene polyamine to conceal nickel ions and copper impurities, solves the technical difficulty that no method for concealing the nickel ions under an acid condition is provided in the past, and also creates a novel method for concealing the copper impurities under the acid condition. According to the method provided by the invention, ascorbic acid is adopted to conceal iron impurities, sodium fluoride is used to conceal aluminum impurities, xylenolorange is used as an indicator under the condition that pH is 5.0 to 5.3, and an EDTA standard solution is used for titrating zinc. By adopting the method for determining the content of the zinc in the alkaline zinc-nickel alloy plating solution, the relative average deviation is 0.35 percent, the recovery rate is 99.4 percent, and the method is simple, rapid, accurate and environmentally friendly.