Abstract: Soybean is an important grain and oil cash crop in China. As one of the main abiotic stress of soybean, saline alkali has negative regulation on the growth and development of soybean, which seriously harms the yield of soybean. In order to analyze the genetic regulation mechanism of salt and alkali on abiotic stress of soybean and help researchers complete the accurate identification of salt and alkali tolerance phenotype, Heihe Branch of Heilongjiang Academy Agricultural Science established the first accurate identification platform of salt and alkali tolerance phenotype of soybean in the main soybean production area in northern Heilongjiang Province in 2022. Using the in-situ saline alkali soil in Daqing Area, three salt alkali resistant gradient tanks, with pH of 10.2, 9.2, and 8.2 for high, medium, and low salt alkali resistant tanks were planed and designed. On the basis of laboratory soil mixing ratio experiments, the soil mixing ratios of high, medium, and low salt alkali tolerant ponds were determined, and the pH changes of high, medium, and low salt alkali tolerant ponds after soil mixing were 10.14±0.07, 9.22±0.19 and 8.13±0.07, respectively. The measured values were basically consistent with the expected theoretical observation values.These results indicated that the pool for the identification of soybean saline-alkali tolerance phenotype established by scientific soil mixing was scientific and feasible, and could be used for the screening and evaluation of soybean saline-alkali tolerance germplasm and breeding of saline-alkali tolerance varieties.