Abstract: In HCl medium, the feasibility of simultaneous determination of p-nitrophenol, p-aminophenol and acetaminophen in the process of synthetic acetaminophen was discussed with equal absorption point and coefficient multiplying power method. The maximum absorption peak of p-nitrophenol is 318 nm; it's linear range is 0～30 mg/L; the measurement wavelength of acetaminophen is 240 nm,it's reference wavelength is 358 nm; themeasurement wavelength of p-aminophenol is 240 nm,272 nm,358 nm and 361 nm. The method has been used in the analysis of three component in the process of synthetic acetaminophen with fast, accurate, trust and simple. It's recovery rate is 92%～106%; it's relative error is ±6%.