Abstract: The design optimization of pile foundation engineering relies on empirical formulas and specification guidance, and it is difficult to fully consider complex geological conditions and construction uncertainty. However, the rapid development of building information model (BIM) technology provides a new perspective for pile foundation design. In this paper, a pile foundation optimization method based on Dynamo is proposed. Through the seamless integration of visual programming tools and BIM technology, an automated pile length calculation and optimization system is formed. The system can automatically adjust the pile length according to the geological conditions. Through the optimization algorithm, the number of pile foundations is reduced, so that the project cost is significantly reduced. The results show that compared with the traditional design, the maximum error between the optimized pile length and the actual square pile length is reduced by 5.8%. Moreover, by introducing the pile group effect coefficient, the number of pile foundations is further optimized. The number of pile foundations on the entire site was reduced by 37.4%, ensuring the economy and reliability of the design. This method not only makes up for the shortcomings of traditional design methods under complex geological conditions, but also provides more efficient technical support for pile foundation engineering.