The traditional algorithm is unable to accurately calculate the ultimate bearing capacity of heavy soil foundation, whereas numerical limit analysis methods can do so precisely. It can be seen that numerical limit analysis can solve geotechnical engineering problems more complex than traditional analytical methods. The incremental load method is used, which applies the principle of failure of engineering materials from quantitative to qualitative changes in stress. As the foundation load gradually increases, the stress on the soil foundation transitions from elastic to plastic, and finally reaches the ultimate failure state, obtaining the corresponding ultimate load value. The ultimate bearing capacity of the foundation under strip foundation load was obtained by combining engineering examples, and compared with the traditional empirical results of Terzaghi, Vesic, and Chen. The results show that the numerical limit analysis method can save 40%, 20%, and similar foundation engineering quantities compared to Terzaghi, Vesic, and Chen empirical methods, respectively. At present, both Terzaghi formula and Vesic formula are applied in practical projects, while Chen formula has not been applied yet.