Abstract: Determination of manganese in ni-based alloy welding materials by Spectrophotometer method is established. The samples are treated with hydrochloric acid and nitric acid, hydrofluoric acid and perchloric acid. After the sample is dissolved, in the acidic solution with silver nitrate catalyst, ammonium persulfate is used to oxidize the divalent manganese to the purple seven-valent manganese.The absorbance is measured at a wavelength of 530 nm, and the content of the sample is calculated based on the working curve. For nickel-based alloy welding materials with different manganese contents, samples are weighed and made up to volume according to the weighing table of this test. Each test step is carried out according to the method, The detection limit is 0.02% , the lower limit is 0.06% , the recoveries ranged from 95.0% to 108.0% , the repeatability is 0.03% , the reproducibility was 0.04% , manganese measurement range: 0.06% -10.0% . which increased the upper limit of manganese content determination compared with the traditional standard method. This method has good precision, Compared with Spark discharge spectrometric analysis, this method has high precision and wide application range for ni-based alloy welding materials. It provides a method reference for wet chemical analysis of Mn in ni-based alloy materials, Promoting the high-quality development of welding technology.