With reference to the evaluations of the typical saturated silt liquefaction potential in the Tianjin area, along with an adjustment in the seismic fortification criterion, in this paper, we discuss the applicability of the standard penetration test method for evaluating soil liquefaction. We collected a great volume of engineering drilling data and investigation results pertaining to the 1976 Tangshan earthquake, compared and analyzed the evaluation results of three methods used in the seismic design codes of China. The results show that the method in the Code for Seismic Design of Buildings (GB50011-2010) has the highest degree of safety in evaluating the liquefaction potential in the Tianjin area at seismic fortification intensities of 7 degrees (0.15g) and 8 degrees (0.20g). This method's accuracy ratio is highest in liquefied areas, but its misjudgment ratio in non-liquefied areas is also high, and the degree of liquefaction determined by this method is more severe than the facts. The accuracy ratio of the method used in the local Code for Investigation of Geotechnical Engineering in liquefied areas is also high, close to that of the current seismic design code, but its misjudgment ratio in non-liquefied areas is relatively reduced compared to the previous method. The degree of liquefaction determined by this method is in good agreement with the facts, which will not only ensure safety, but also reflect a certain degree of economy, making it more suitable for evaluating the silt liquefaction potential in the Tianjin area.